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Biomedical subjects

N Schmitz

Publications and source records attributed to N Schmitz.

At least 163 records · Page 9Linked to original sources
PubMed1995

Underestimation of sensorimotor task-induced blood-pressure changes by posttask sphygmomanometry.

For assessment of cardiovascular effects of sensorimotor work, blood pressure is commonly measured by arm sphygmomanometry. A technique introduced by Penaz makes it feasible to monitor blood pressure noninvasively and continuously from the finger artery which measures give high correlations with intraarterial measurement. This study compared blood-pressure changes induced by a standard sensorimotor task using sphygmomanometry and the Penaz-method. It was investigated whether sphygmomanometrically recorded blood pressure can be used to estimate task-induced blood-pressure changes and whether inflating the cuff to different maximum pressures induces blood-pressure changes. 46 normotensive individuals were randomly assigned to the discomfort group (maximum arm-cuff pressure of 280 mmHg) or to the control group (maximum arm-cuff pressure of 160 mmHg). The experiment consisted of six tasks of 4 min. each. Results indicated that sphygmomanometries under-estimated task-induced blood-pressure changes and that phasic systolic and diastolic blood-pressure elevations during the task were leveled off shortly after the end of the task. Effects of 'cuff-inflation hypertension' were not found. The Penaz-method appears to be more appropriate than sphygmomanometry if dynamic aspects of blood pressure are of interest.

Adult↗
PubMed1995

G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: comparison of T cell depletion strategies using different CD34+ selection systems or CAMPATH-1.

Allogeneic transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPC) appears to be an attractive alternative to allogeneic bone marrow transplantation (BMT). However, because vast amounts of potentially graft-vs.-host-reactive T cells are transfused with PBPC grafts, the use of PBPC in the allogeneic setting may be associated with an increased incidence or severity of graft-vs.-host disease (GVHD). To evaluate strategies for prevention of GVHD after PBPC allografting, we have studied T cell depletion (TCD) of G-CSF-mobilized PBPC samples harvested from six healthy donors and from five patients scheduled for autologous PBPC transplantation. Three approaches (CAMPATH-1 plus autologous complement [C], immunomagnetic CD34+ cell selection, and biotin-avidin-mediated CD34+ cell selection) were compared. TCD of PBPC samples with the monoclonal antibody (MAb) CAMPATH-1 plus autologous C resulted in a median elimination of 2.16 log CD3+ T cells, whereas 39% of CD56+ natural killer (NK) cells and 56% of CD34+ progenitor cells were recovered. TCD by CD34+ cell selection with the Isolex (Baxter, Munich, Germany) or Ceprate (CellPro, Bothell, WA) devices achieved median depletions (Isolex vs. Ceprate) of 4.04 vs. 3.12 log T cells and > 5 vs. 3.27 log NK cells while allowing the recovery of 36 vs. 27% CD34+ cells. The median purity of CD34+ cells in the final product was 1.7 (CAMPATH-1), 94 (Isolex), and 65% (Ceprate). We conclude that all methods tested effectively deplete T cells from PBPC preparations harvested from healthy donors. Whereas immunomagnetic CD34+ selection is most effective in terms of elimination of T cells, the less intensive T and NK cell depletions achieved with CAMPATH-1 might be advantageous with regard to retaining engraftment potential and graft-vs.-leukemia (GVL) activity of PBPC allografts.

Adolescent↗
PubMed1995

Results of a randomised, controlled, multicentre study of recombinant human granulocyte colony-stimulating factor (filgrastim) in patients with Hodgkin's disease and non-Hodgkin's lymphoma undergoing autologous bone marrow transplantation.

In 54 patients with malignant lymphoma, haematopoietic recovery after high-dose chemotherapy and autologous bone marrow transplantation (BMT) was compared between patients randomised to receive 10 or 30 micrograms/kg/day of r-metHuG-CSF (filgrastim) or no growth factor. After standard high-dose chemotherapy with cyclophosphamide, etoposide and BCNU (CVB regimen for patients with Hodgkin's disease) or BCNU, etoposide, cytosine arabinoside and melphalan (BEAM regimen for patients suffering from non-Hodgkin's lymphoma) followed by autologous BMT, r-metHuG-CSF was administered by continuous intravenous infusion from the first day after autologous BMT until neutrophil recovery. When the r-metHuG-CSF groups were compared with the control group the major findings were: the median time to reach an absolute neutrophil count (ANC) > or = 0.5 x 10(9)/L was 20 days in the control group and 12 and 14 days, respectively, in the r-metHuG-CSF groups (P = 0.0004). The duration of neutropenia (ANC < 0.5 x 10(9)/L) was reduced from 27 days in the control group to 11 and 13 days in the r-metHuG-CSF groups (P = 0.0001). In addition, fewer days of febrile neutropenia were observed in the r-metHuG-CSF groups (5 and 6 days) than in the control group (10 days; P = 0.036). No significant effects of r-metHuG-CSF administration on the number of days with fever, the use of intravenous antibiotics and hospitalisation were detected. R-metHuG-CSF was well tolerated without any serious side-effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Rapid engraftment of peripheral blood progenitor cell grafts purged with B cell-specific monoclonal antibodies and immunomagnetic beads.

PBPC harvesting was performed in two patients with advanced-stage low-grade non-Hodgkin's lymphoma after mobilization with dexa-BEAM chemotherapy plus G-CSF. The collected grafts were subjected to immunomagnetic purging using B cell-specific moAbs and paramagnetic beads. Immunophenotypic and/or molecular analysis of the resulting products (PCR amplification of t(14;18) or CDR-III rearrangements) demonstrated successful depletion of lymphoma cells. Rapid and durable hematopoietic recovery occurred after reinfusion of the purged grafts following myeloablative radiochemotherapy (9-10 days to neutrophils > 0.5 x 10(9)/l; 9-11 days to platelets > 20 x 10(9)/l). We conclude that effective immunomagnetic purging of PBPC grafts is feasible without affecting engraftment.

Antibodies, Monoclonal↗
PubMed1995

Allogeneic transplantation of peripheral blood progenitor cells.

Transplantation of autologous peripheral blood progenitor cells (PBPC) is now a well established method to reconstitute haematopoiesis after high-dose chemoradiotherapy. Allogeneic PBPCs have rarely been used as the sole measure to induce haematopoietic recovery after myeloablative therapy because of uncertainties regarding the durability of engraftment and the risk of acute and chronic graft-vs-host disease (GVHD). In addition, this technique requires the exposure of normal donors to granulocyte colony stimulating factor (G-CSF) in order to mobilise a sufficient number of PBPCs which can then be collected by leukapheresis. We report here our initial experience with allogeneic transplantation of PBPCs in order to demonstrate the feasibility and safety of harvesting sufficient numbers of PBPCs in healty donors. In addition, the early results presented in this communication show that allogeneic PBPCs can successfully be used to restore haematopoiesis in HLA-identical siblings of the donor without causing devastating graft-vs-host disease.

Antigens, CD34↗
PubMed1994

[Physical and aerodynamic airflow relations of the air stream of the Micro-Air aesthesiometer].

BACKGROUND: In an experimental study we examined the aerodynamical airstreamprofile of a new airstream aesthesiometer. With this instrument it is possible to measure corneal sensitivity without touching the cornea. METHOD: A constant hotwire-anemometer was used to measure the 0.5 s air impulse in different distances. The corneal topographic sensitivity was measured at 45 probands, age 20 to 80. RESULTS: The investigations show that the laminar air stream within the 0.2 mm wide nozzle changes after withdrawal, in regards to stream profile, jet width and speed. The parabolashaped stream profile passes over through the air matrix and changes into a bell-shaped profile. The stream properties of the circular free system imply that the air stream in a 4 mm distance is nearly half as wide and double as high or fast in comparison to an 8 mm distance. The corneal sensitivity measured with the CMA showed in comparison to the Draeger aesthesiometer a lower sensitivity than in the periphery. CONCLUSION: A clinical use for measuring corneal sensitivity with the CMA can not be recommended.

Adult↗
PubMed1994

G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: safety, kinetics of mobilization, and composition of the graft.

Allogeneic transplantation of peripheral blood progenitor cells (PBPC) makes the general anaesthesia of the donor unnecessary and may result in more rapid engraftment and faster recovery of the immune system. We have studied G-CSF-mediated PBPC mobilization in healthy donors and analysed the cellular composition of the resulting PBPC grafts. PBPC grafts were obtained from nine healthy donors (18-67 years old) for allogeneic or syngeneic transplantation. Six donors received 10 micrograms/kg G-CSF per day, the others 5-6 micrograms/kg. Mobilization and harvesting were well tolerated except for moderate bone pain which occurred in all donors primed with 10 micrograms/kg. With 10 micrograms/kg, a 31-fold (9-62) enrichment of circulating CD34+ cells was observed with peak values constantly occurring on day 5 after the start of G-CSF administration. Starting harvest on day 5, one to three collections on consecutive days yielded 5.5 x 10(6)/kg (0.9-10.7) CD34+ cells, 219 x 10(6)/kg (106-314) T cells, and 34 x 10(6)/kg (23-67) NK cells per 10 litres leukapheresis volume. Altogether, PBPC grafts contained 3 times more CD34+ cells, 7 times more T cells, and 20 times more NK cells than five allogeneic marrow grafts that were analysed for comparison. The yield of CD34+ cells per 10 litres apheresis volume as well as the height of the CD34+ peak in peripheral blood were inversely correlated to the age of the donor. In the donors primed with 5-6 micrograms/kg G-CSF the increase of circulating CD34+ cells (4-7-fold enrichment) and the CD34+ cell yield per 10 litres leukapheresis volume (1 x 10(6)/kg [0.8-2.2]) was much smaller compared with the 10 micrograms/kg group. In conclusion, sufficient amounts of PBPC capable of restoring haemopoiesis in allogeneic recipients can be mobilized safely by administration of G-CSF (10 micrograms/kg s.c. for 5 d) in healthy donors, and harvested with one or two leukapheresis procedures. Whether the large numbers of T-cells and NK cells that are contained in the collection products may influence graft-versus-host and graft-versus-leukaemia reactivities of PBPC grafts remains to be determined.

Adolescent↗
PubMed1994

Dexa-BEAM in patients with Hodgkin's disease refractory to multidrug chemotherapy regimens: a trial of the German Hodgkin's Disease Study Group.

PURPOSE: A prospective phase II study was conducted to evaluate the efficacy of dexamethasone, carmustine, etoposide, cytarabine, and melphalan (Dexa-BEAM) as salvage chemotherapy for patients with Hodgkin's disease. PATIENTS AND METHODS: Fifty-five patients progressing on or relapsing after eight- or 10-drug chemotherapy (cyclophosphamide, vincristine, procarbazine, and prednisone plus doxorubicin, bleomycin, vinblastine, and dacarbazine [COPP+ABVD] or COPP+ABV+ifosfamide, methotrexate, etoposide, and prednisone [IMEP]) were treated with Dexa-BEAM. Patients who responded after two cycles of Dexa-BEAM either continued treatment for another two to three cycles or received high-dose chemotherapy/autologous bone marrow transplantation (HDCT/ABMT) with cyclophosphamide, etoposide, and carmustine (BCNU) (CVB) as conditioning regimen. RESULTS: Seventeen patients (31%) achieved a complete remission and 16 (29%) a partial remission, resulting in a response rate of 60% (95% confidence interval, 46% to 73%). Progressive disease developed in 18 patients. Toxicity of Dexa-BEAM was acceptable with pronounced, but temporary World Health Organization (WHO) grade III/IV granulocytopenia and thrombocytopenia occurring in more than 90% of all courses. Two patients died of sepsis during granulocytopenia. Three prognostic subgroups could be distinguished: (1) patients progressing on initial chemotherapy, (2) patients relapsing within 12 months, and (3) patients with late relapses. The response rates for these groups were 52%, 60%, and 83%, and the median survival duration 12, 29, and 40+ months, respectively. In a nonrandomized comparison, the survival of patients who responded to two cycles of Dexa-BEAM and had additional cycles of Dexa-BEAM (n = 14) was not different from those responding patients who underwent HDCT/ABMT (n = 19). However, the power to detect a 20% survival difference was only 33% in this comparison. CONCLUSION: Dexa-BEAM is an effective salvage treatment for patients with Hodgkin's disease who fail to respond to multidrug chemotherapy. Efficacy and toxicity are comparable to HDCT/ABMT and underline the need for prospective randomized trials to define better the role of HDCT with and without ABMT in these patients.

Adult↗
PubMed1994

[Measuring corneal sensitivity with the air aesthesiometer in comparison with the Draeger electromagnetic air aesthesiometer].

A new air aesthesiometer developed by S. Weinstein was tested with an anemometer device. It could be shown that the air stream is not linear. The normal sensitivity threshold pattern was measured in 271 probands varying in age from 10 to 98 years. In a comparative study we measured the corneal sensitivity of 20 patients after penetrating keratoplasty with the air aesthesiometer and the Draeger electromechanical aesthesiometer. Because of the aerodynamic broadening of the airstream it was not possible to measure corneal sensitivity at the transplant periphery or host cornea with the new device, while we could demonstrate corneal nerve fibre degeneration at the host cornea or regeneration of the transplant with the electromechanical aesthesiometer.

Adolescent↗
PubMed1994

Rise in systolic blood pressure during sphygmomanometry depends on the maximum inflation pressure of the arm cuff.

OBJECTIVE: Sphygmomanometric recordings of blood pressure are a standard technique in clinical practice. We investigated whether arm-cuff inflation can induce short-term blood pressure changes ('cuff-inflation hypertension'), limiting the generalizability of recordings. METHODS: Progress in biomedical methodology makes it feasible to monitor blood pressure continuously and non-invasively at the finger artery (the Peñaz method). Seventy-two normotensive subjects were randomly assigned either to a series of sphygmomanometric recordings in which a maximum cuff pressure of 300 mmHg was applied, to a series in which the maximum cuff pressure was 175 mmHg or to a control group in whom no sphygmomanometric recordings were made. RESULTS: The subjects exposed to arm-cuff inflations perceived the cuff inflation pressure, but their perception could not differentiate between the two maximum cuff pressures. Furthermore, increases in systolic blood pressure during the inflation period were recorded when a maximum cuff pressure of 300 mmHg was applied. The effects on diastolic blood pressure were not significant. CONCLUSIONS: The maximum arm-cuff pressure during sphygmomanometry should be not too far above the pressure needed to occlude the brachial artery. A high maximum arm-cuff pressure increases the chances of inducing 'cuff-inflation hypertension'.

Adult↗