Biomedical subjects

Jang-Soo Suh

Publications and source records attributed to Jang-Soo Suh.

8 recordsLinked to original sources

PubMed2005

Rapid cell-deformability sensing system based on slit-flow laser diffractometry with decreasing pressure differential.

A slit-flow apparatus with a laser-diffraction method has been developed with significant advances in ektacytometry design, operation and data analysis. In the slit-flow ektacytometry, the deformation of red blood cells subjected to continuously decreasing shear stress in slit-flow can be quickly measured with adopting a laser-diffraction technique. Both the laser-diffraction image and pressure were measured with respect to time, which enable to determine the elongation index (EI) and the shear stress. The range of shear stress is 0-35 Pa and the measuring time is < 2 min. The EI is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The present study proposed the deformability index (DI) as a new measure of the RBC deformability, which is defined as an integral area under the EI curve between 0 and tau10 (tau(w) = 0-10). The key advantage of this design is the incorporation of a disposable element that holds the blood sample, which enables the present system to be easily used in a clinical setting.

Biosensing Techniques↗

PubMed2005

Slit-flow ektacytometry: laser diffraction in a slit rheometer.

BACKGROUND: Deformability of red blood cells (RBCs) is a determinant of blood flow resistance as RBCs pass through small capillaries of the microcirculation. Available techniques for measuring RBC deformability often require a washing process after each measurement, which is not optimal for day-to-day clinical use. METHODS: A laser diffraction technique has been combined with slit-flow rheometry, which shows significant advances in ektacytometric design, operation, and data analysis. The essential features of this design are its simplicity (ease of operation and no moving parts) and a disposable element that is in contact with the blood sample. RESULTS: With slit ektacytometry, the deformation of RBCs subjected to continuously decreasing shear stress in a slit flow can be quickly measured with extremely small quantities of blood. The measurements with the slit ektacytometer were compared with those of LORCA and a strong correlation was apparent. The deformability of the hardened RBCs was markedly lower than that of the normal RBCs. In addition, the young cells showed higher values of the elongation index than did the old cells. CONCLUSIONS: The newly developed slit ektacytometer can measure RBC deformability with ease and accuracy. In addition, the slit ektacytometer can be easily used in a clinical setting owing to the incorporation of a disposable element that holds the blood sample.

Adult↗

PubMed2004

Outcome of allogeneic peripheral blood stem cell transplantation using matched sibling donors in patients with high-risk hematological diseases.

Although the use of peripheral blood stem cells instead of bone marrow is still a matter of debate in transplantation from HLA-identical sibling donors, allogeneic peripheral blood stem cell transplantation (PBSCT), with a stronger graft-versus-leukemia (GVL) effect, may be preferable as a source of stem cells, especially in the case of advanced hematologic diseases. As such, the current paper reports on the outcomes of 27 consecutive patients with high-risk hematologic diseases treated with allogeneic PBSCT. The median dose of CD34+, CD3+ cells, and MNC infused was 8.18 x 10(6)/kg (range: 2.78-14.93), 1.50 x 10(8)/kg (range: 0.06-4.25), and 7.17 x 10(8)/kg (range: 0.95-15.85), respectively. The median time taken for the ANC and platelets to reach 500 and 20,000 x 10(6)/microL was 15 (range: 9-25) and 16 d (range: 10-56), respectively. Three patients (11.1%) experienced transplant-related mortality within 90 d of transplantation, and 15 (62.5%) of 24 evaluated patients developed chronic graft-versus-host disease (GVHD; six limited, nine extensive). There was a significant difference in overall survival (OS) between the group with chronic GVHD and the group without chronic GVHD (P = 0.0253). The causes of death included relapse (six cases) and non-relapse mortality (infection: four cases, chronic GVHD-related death: three cases). The 4-yr OS rate and disease-free survival rate was 43.3 +/- 10.9% and 35.8 +/- 10.2%, respectively. Accordingly, chronic GVHD was found to have a positive role in patients with high-risk hematologic diseases that received allogeneic PBSCT.

Adolescent↗

PubMed2004

Blood flow resistance with vibration and its effect on blood cell migration.

The present study investigated the effect of transverse vibration on the hemo-rheological characteristics of blood flow using a newly designed pressure-scanning capillary viscometer. As a transverse vibration was applied, aggregated blood cells become disaggregated. Frequency of vibration was found to be the main parameter causing hemo-rheological changes. For RBC suspension in a non-aggregating medium (Dextran 40), increasing frequency of vibration caused decreased flow resistance. Meanwhile, flow resistance for whole blood increased with frequency of vibration. These seemingly contradictory results could be interpreted without conflict when a comprehensive mechanism of cell migration under vibration is elucidated. The present study confirmed that vibration diminishes RBC aggregation, which triggers two different cell migration mechanisms and subsequently resulted in either increasing or decreasing the flow resistance.

Blood Flow Velocity↗

PubMed2004

Measurement of blood viscosity using a pressure-scanning capillary viscometer.

A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.

Blood Viscosity↗

PubMed2003

Characteristics of blood flow resistance under transverse vibration: red blood cell suspension in Dextran-40.

Vibration under shear flow causes the reduction of flow resistance for shear-thinning fluids. The present study investigates the effect of vibration on the flow resistance of a nonaggregating red blood cell (RBC) suspension with a newly designed pressure-scanning capillary viscometer (PSCV). The PSCV was originally designed to measure non-Newtonian viscosity continuously over a range of shear rates at a time, which was slightly modified and used for the present study. Low-frequency vibration was applied perpendicular to the direction of the flow. The effect of the transverse vibration was investigated for both Newtonian fluids and nonaggregating RBC suspensions. The experimental results showed that the vibration had no effect on the flow resistance of the Newtonian fluids. However, the vibration caused a reduction of the flow resistance of the RBC suspension. The reduction of the flow resistance was strongly dependent on both frequency and amplitude of vibration.

Blood Flow Velocity↗

PubMed2002

A histopathologic study of the nervous system after inhalation exposure of 1-bromopropane in rat.

1-Bromopropane (1-BP) has recently become known as an alternative cleaning material with less damage to the ozone layer. However, its toxicity is not fully evaluated. This study was designed to investigate the repeated inhalation toxicity of 1-BP on the nervous systems in Sprague-Dawley rats. The experiment was done by repeated exposure of the rats to 0, 200, 500, and 1250 ppm for 6 h per day, 5 days a week, for 13 weeks, respectively. Morphologic studies were done for the central nervous system, sacral and peroneal nerves. The serial sections of the brain and spinal cord of 1-BP inhalation groups revealed no pathological features either in the gray or white matter. The nerve fiber teasing, light and electron microscopic studies of the sacral and peroneal nerve fibers showed no significant difference between 1-BP inhalation groups and the control group. From these results, it is concluded that the nervous system is histologically resistant to the repeated inhalation of 1-BP up to 1250 ppm for 13 weeks. Experiments with higher concentrations of 1-BP and the functional studies are necessary to clarify the 1-BP toxicity.

Animals↗

PubMed2002

Prophylactic growth factor-primed donor lymphocyte infusion using cells reserved at the time of transplantation after allogeneic peripheral blood stem cell transplantation in patients with high-risk hematologic malignancies.

BACKGROUND: Standard allogeneic bone marrow transplantation (BMT) offers only a small chance of cure for most adult patients with advanced hematologic malignancies. The authors postulated that allogeneic peripheral blood stem cell transplantation (PBSCT) followed by prophylactic growth factor-primed donor lymphocyte infusion (DLI) with cells reserved at harvest would maximize the graft-versus-tumor effects in patients with hematologic malignancies who had a high risk of recurrence. METHODS: Seventeen patients with hematologic malignancies who had a high risk of recurrence were allocated on an intent-to-treat basis to allogeneic PBSCT from human leukocyte antigen-matched sibling donors followed by prophylactic growth factor-primed DLI of cells reserved at harvest for transplantation. RESULTS: The median age was 37 years (range, 19-56 years). All donors underwent two or more apheresis procedures. The median numbers of mononuclear cells (MNCs), CD34 positive (CD34+) cells, and CD3+ cells, respectively, that were collected for 17 donors were 9.0 x 10(8) MNCs/kg (range, 4.9-14.4 x 10(8) MNCs/kg), 13.0 x 10(6) CD34+ cells/kg (range, 2.4-75.2 x 10(6) CD34+ cells/kg), and 5.8 x 10(8) CD3+ cells/kg (range, 3.3-9.9 x 10(8) CD3+ cells/kg) for a mean number of 2.35 apheresis procedures (range, 2.0-4.0 procedures). The median numbers of MNCs and CD3+ cells that were cryopreserved were 2.1 x 10(8) MNCs/kg (range, 0.0-4.4 x 10(8) MNCs/kg) and 1.4 x 10(8) CD3+ cells/kg (range, 0.0-3.5 x 10(8) CD3+ cells/kg). Seven of 17 patients received additional PBSCs, with a median of 5.0 x 10(7) CD3+ cells/kg (range, 3.0-9.9 CD3+ cells/kg) between Day 41 and Day 120. The reasons for inability to administer additional PBSCs in 10 patients included early death (n = 4 patients), severe graft-versus-host disease (GVHD) (n = 3 patients), disease recurrence (n = 2 patients), and harvest failure (n = 1 patient). Of seven patients, two patients died of recurrence, and one died of cytomegalovirus pneumonitis. The surviving four patients were free of disease when last assessed (median follow-up, 597 days) but were suffering from chronic GVHD (one patient had limited GVHD, and three patients had extensive GVHD). CONCLUSIONS: The authors suggest that allogeneic PBSCT with prophylactic growth factor-primed DLI may be a potentially curative strategy for the treatment of hematologic malignancies in patients with a high risk of recurrence. Their approach may offer the additional advantage of collecting enough cells at harvest for the potential use of DLI, which is easy, convenient for donors, and cost effective.

Adult↗