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Biomedical subjects

K Sagawa

Publications and source records attributed to K Sagawa.

At least 37 records · Page 2Linked to original sources

Glucocorticoid-induced alterations of renal sulfate transport.

Glucocorticoid administration decreases renal sodium/phosphate cotransport in the proximal tubule due to a down-regulation of the sodium/phosphate cotransporter but has no effect on the sodium-dependent transport of glucose or proline. The objectives of the present investigation were to determine the effects of the glucocorticoid methylprednisolone (MPL) on 1) inorganic sulfate renal clearance in rats in vivo, 2) sodium/sulfate cotransport in kidney cortex membrane vesicles, and 3) the cellular mechanism of the MPL-induced alterations in sulfate renal transport. Male adrenalectomized Wistar rats received an i.v. dose of 50 mg/kg MPL or the vehicle. Urine samples were collected for 12 h after the administration of MPL, and blood samples were collected at the midpoint of the urine collection. Other animals were sacrificed at 4, 6, and 12 h after MPL administration, and the kidney cortex was removed for RNA or membrane preparations. Kidney cortex sodium/sulfate cotransporter (NaSi-1) mRNA levels were determined by reverse transcription-polymerase chain reaction and NaSi-1 protein levels were determined by enzyme-linked immunosorbent assay. The urinary excretion rate and renal clearance of sulfate were significantly increased in MPL-treated animals (144.0 +/- 27.0 versus 65.3 +/- 21.3 micromol/12 h/kg and 0.208 +/- 0.038 versus 0. 078 +/- 0.025 ml/min/kg, mean +/- S.E., n = 9-12 in treated versus control). The V(max) value for sodium-dependent sulfate transport in brush border membrane vesicles (representing reabsorption in the proximal tubules) was significantly decreased in MPL-treated animals compared with controls (0.68 +/- 0.07 versus 0.88 +/- 0.05 nmol/mg of protein/10 s, mean +/- S.E.). There was no change in the K(m) value for sodium/sulfate cotransport in brush-border membrane and no change in sulfate/anion exchange in basolateral membrane vesicles. Membrane fluidity in brush border membrane and basolateral membrane vesicles, determined by the fluorescence polarization of 1, 6-diphenyl-1,3,5-hexatriene was unaltered by MPL treatment. NaSi-1 mRNA levels were significantly decreased at 4 and 6 h, but not 12 h, after MPL administration, whereas NaSi-1 protein expression was significantly decreased at 4, 6, and 12 h. Therefore, MPL treatment increases the renal clearance of inorganic sulfate, at least in part, due to down-regulation of NaSi-1 mRNA and protein expression in the kidney.

Animals↗

Molecular cloning of a glycosylphosphatidylinositol-anchored molecule CDw108.

CDw108, also known as the John-Milton-Hagen human blood group Ag, is an 80-kDa glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein that is preferentially expressed on activated lymphocytes and E. The molecular characteristics and biological function of the CDw108 were not clarified previously. In this manuscript, we identify the cDNA clone containing the entire coding sequence of the CDw108 gene and report its molecular characteristics. The 1998-base pairs of the open reading frame of the cloned cDNA encoded a protein of 666 amino acids (aa), including the 46 aa of the signal peptide and the 19 aa of the GPI-anchor motif. Thus, the membrane-anchoring form of CDw108 was the 602 aa, and the estimated molecular mass of the unglycosylated form was 68 kDa. The RGD (Arg-Gly-Asp) cell attachment sequence and the five potential N-linked glycosylation sites were located on the membrane-anchoring form. Flow cytometric and immunoprecipitation analyses of the CDw108 cDNA transfectants confirmed that the cloned cDNA encoded the native form of CDw108. The CDw108 mRNA was expressed in activated PBMCs as well as in the spleen, thymus, testis, placenta, and brain, but was not expressed in any other tissues tested. Radiation hybrid mapping indicated that the CDw108 gene was located in the middle of the long arm of chromosome 15 (15q23-24). This molecular information will be critical for understanding the biological function of the CDw108 Ag.

Amino Acid Sequence↗

Effect of experimentally induced hypothyroidism on sulfate renal transport in rats.

Decreased serum sulfate concentrations are observed in hypothyroid patients. However, the mechanism involved in thyroid hormone-induced alterations of renal sulfate homeostasis is unknown. The objectives of this investigation were to determine the effect of 6-propyl-2-thiouracil (PTU)-induced hypothyroidism in rats on 1) the in vivo serum concentrations, renal clearance, and renal reabsorption of sulfate, 2) the in vitro renal transport in brush-border membrane (BBM) and basolateral membrane (BLM) vesicles, and 3) the cellular mechanism of the hypothyroid-induced alteration in sulfate renal transport. Serum sulfate concentrations, renal fractional reabsorption of sulfate, and creatinine clearance were decreased significantly in the hypothyroid group. The Vmax values for sodium-sulfate cotransport in BBM were significantly decreased in the kidney cortex from the hypothyroid animals (0.90 +/- 0.31 vs. 0.49 +/- 0.08 nmol. mg-1. 10 s-1, n = 5-6, P < 0.05) without changes in Km. There were no significant differences in Vmax and Km for sulfate/anion exchange transport in BLM. Sodium-dependent sulfate transporter (NaSi-1) mRNA and protein levels were significantly lower in the kidney cortex from hypothyroid rats. Hypothyroidism did not alter the membrane motional order (fluidity) in BBM and BLM, which indicates that the changes in the membrane fluidity do not represent the mechanism for the altered renal transport. These results demonstrate that PTU-induced hypothyroidism decreases sodium-sulfate cotransport by downregulation of the NaSi-1 gene.

Animals↗

Age- and growth hormone-induced alterations in renal sulfate transport.

The effects of growth hormone (GH) treatment on renal sodium sulfate cotransport (NaSi-1) were studied in adult (9-10 months) and old (22-23 months) male Fischer 344 rats. All animals received twice-daily s.c. injections of recombinant human GH (hGH; 4 mg/kg) for up to 6 days. Animals were sacrificed by exsanguination on days 0, 1, 2, 3, 4, 5, and 6. Kidneys were removed, and kidney cortex was trimmed immediately and used for RNA and membrane preparations. Plasma hGH concentrations were significantly lower in old rats during the hGH treatment (P <.05). Insulin-like growth factor-I (IGF-I) levels were significantly increased and remained stable after day 2 of hGH treatment in both age groups (P <.05). There was no significant difference in plasma IGF-I levels between age groups. Plasma IGF-I binding protein 3 (IGFBP-3) concentrations were significantly higher in 9- to 10-month-old rats compared with that in 22- to 23-month-old animals (P <.001). There were no significant differences in plasma IGFBP-3 concentrations between days of hGH treatment. The NaSi-1 mRNA levels were significantly lower in 22- to 23-month-old rats compared with that in 9- to 10-month-old animals (P <.001). The NaSi-1 mRNA levels were significantly increased on days 2 and 3 of hGH treatment (P <.05) and then gradually decreased to the control value. The NaSi-1 protein levels in old animals (22-23 months) were also significantly lower than that of 9- to 10-month-old animals and were significantly increased from day 2 of hGH treatment, reaching a maximum level on day 3 or 4 and then returning to the baseline level in both age groups. From these results, it was concluded that 1) NaSi-1 mRNA and protein levels are lower in old animals and increase in both adult and aged rats after hGH treatment, 2) plasma IGF-I levels are similar in adult and aged rats and increase after hGH treatment, and 3) plasma IGFBP-3 levels are lower in old rats and remain unchanged after hGH treatment.

Aging↗

The effects of an angiotensin-converting inhibitor (enalapril) on patients with mild cardiac failure--evaluating cardiac function based on the relationship between daily walking pace and heart rate.

BACKGROUND: Heart failure has been evaluated by several methods, the New York Heart Association (NYHA) classification of heart failure based on symptoms being used most frequently. However, the degree of heart failure assessed by these criteria does not always correlate with cardiac function in daily life. HYPOTHESIS: The aim of the study was to evaluate cardiac function based on the walking pace/heart rate (HR) relationship to assess the effects of enalapril, an angiotensin-converting enzyme inhibitor, in patients with mild to moderate cardiac function. METHODS: To evaluate cardiac function objectively, we developed a method using a pedometer to count the steps walked while simultaneously recording HR using a Holter electrocardiograph (ECG). Step-count walk rate (WR) was recorded on the magnetic tape of the Holter apparatus, and both HR and walking pace were calculated automatically by the Holter ECG analysis system. Data were determined every hour, and mean pace and HR were plotted along the x and y axes, respectively. The slope of HR x WR was calculated using the least squares method. The slope and the total number of steps were regarded as indicators of cardiac function and quality of life, respectively. We analyzed 36 subjects, consisting of 8 normal volunteers, 8 patients in New York Heart Association (NYHA) class I. 11 in class II, and 9 in class III chronic mild heart failure, during maximal exercise work load by bicycle ergometer; furthermore, fractional shortening of the left ventricle on echocardiogram was determined in 14 patients with chronic mild heart failure and was compared with the slope of HR x WR. Enalapril was administered at a daily dose of 2.5-10 mg for 1-24 months (mean 6 months) in 60 patients to evaluate the effects of this drug on these parameters. RESULTS: There was a significant inverse relationship between maximal work load and the HR x WR slope, and also between the fractional shortening and the slope, suggesting that the slope may reflect the severity of cardiac dysfunction. Furthermore, the slope decreased significantly from 1.8 +/- 1.26 before enalapril to 1.0 +/- 0.94 (mean +/- standard deviation) after drug administration, while the total number of steps increased significantly from 4842 +/- 3581 to 7804 +/- 4793. CONCLUSION: The slope of the graph relating step count and HR proved to be a good, objective indicator of cardiac function, and enalapril therapy improved this parameter.

Adolescent↗

Detection and quantitation of a sodium-dependent sulfate cotransporter (NaSi-1) by sandwich-type enzyme-linked immunosorbent assay.

The sodium-dependent sulfate transporter (NaSi-1) DNA has been recently identified from rat kidney cortex. The objective of this study was to develop a quantitative assay for the NaSi-1 transporter protein. The NaSi-1 antigen was prepared by fusion protein techniques following analysis of the primary sequence for antigenicity. Polyclonal and monoclonal antibodies against the NaSi-1 antigen were raised in rabbits and mice, respectively. The specificity of the raised antibodies was examined by Western analysis using brush-border membrane (BBM) and basolateral membrane (BLM) purified from rat kidney cortex. Both NaSi-1 polyclonal and monoclonal antibodies detected a 69-kDa protein in the BBM. Using the purified monoclonal antibody as the capture antibody and the polyclonal antibody as the detecting antibody, a simple and sensitive sandwich-type enzyme-linked immunosorbent assay was developed to quantitate NaSi-1 transporter protein levels in tissue. The specificity of the assay was examined using BBM, BLM and NaSi-1-transfected Madin-Darby canine kidney cells. The assay was capable of detecting NaSi-1 at levels as low as 6.58 fmol. The concentration of NaSi-1 transporter protein in crude membrane isolated from rat kidney cortex was 0.094+/-0.014 fmol/ microg protein (mean+/-SD of three preparations).

Animals↗

Abnormal neurohumoral responses to exercise in patients with heart disease: inhibition of an increase in endothelin-1 production during exercise.

We have reported that the plasma endothelin-1 (ET-1) level is significantly increased by exercise in healthy athletes and that it is elevated in the circulation of the non-working leg but not the working leg, suggesting that ET-1 plays an important role in redistribution of blood during exercise. This study was designed to compare alterations of neurohumoral substances by exercise in normal subjects and patients with heart disease. Study patients comprised three groups: eight patients with congestive heart failure (CHF) due to Ebstein's anomaly or single-ventricle heart after Fontan operation; six patients with complete transposition of the great arteries (TGA) after an anatomic surgical correction who may be candidates for ischemic heart disease; and five age-matched normal subjects. All patients were in New York Heart Association functional class I. All subjects performed symptom-limited treadmill exercise. It is suggested that patients with CHF or TGA have a manifest or latent exercise intolerance, respectively. In failed to increase plasma ET-1 level, although it caused a greater increase in norepinephrine, angiotensin II, and arginine vasopressin than in the controls. Exercise also caused a delay in the increased response of plasma ET-1 levels in patients with TGA after an anatomic surgical repair. On the other hand, plasma brain natriuretic peptide (BNP) level was augmented by exercise in patients with CHF and patients with TGA but not in the controls. The present results suggest that an increase in ET-1 production during exercise is absent in patients with heart disease. The mechanisms of inhibition of ET-1 production during exercise in patients with heart disease remain to be elucidated. However, the present study suggests that ET-1 plays an important role in redistribution of blood during exercise, and proposes the possibility that failure of an increase in ET-1 production results in exercise intolerance in patients with heart disease.

Child↗

Monoclonal antibody NU-B1 reacts with novel antigen on human B cells in mantle and marginal zones distinct from known CD molecules.

To analyze the cellular antigens of human B-cell lineage, a monoclonal antibody, NU-B1, was raised using the acute lymphoblastic leukemia (ALL) cell line NALM-16 as the immunogen. NU-B1 reacted with 7.7+/-3.9% of the healthy adult peripheral blood mononuclear cells but not with neutrophils, monocytes, red blood cells or thymocytes. In order to distinguish the reaction specificity of NU-B1, two-color immunofluorescence staining using tonsillar cells was performed, and it was demonstrated that NU-B1-positive cells coexpressed CD20, which is a representative B-cell antigen. The expression of NU-B1 was highly restricted to cells of B-cell lineage when a panel of hematopoietic cell lines was examined. In a pathoimmunohistological study using human lymph node tissue, NU-B1-positive cells were localized in the mantle and marginal zones. In a clinical study, NU-B1 reacted specifically with leukemias/lymphomas of B-cell lineage: all 43 cases of ALL including common ALL and biphenotypic leukemia, all 4 cases of B-cell ALL, 6/7 B-cell type malignant lymphomas and 2/4 B-cell chronic lymphocytic leukemias. NU-B1 did not react with multiple myeloma, T-cell or myeloid leukemias/lymphomas. Immunoprecipitation of NU-B1 revealed two clear bands at 50 kDa and 42 kDa under either reducing or nonreducing conditions. Although anti-IgM treatment induced dramatic down modulation of CD79b, the NU-B1 antigen was also down modulated, but only slightly. However, crosslinking of NU-B1 did not induce tyrosine phosphorylation of intracellular proteins or the mobilization of calcium in NALM-16. The present results revealed that the antigenic determinant recognized by NU-B1 is not surface immunoglobulin chains, HLA-DR, a receptor for C3, Fc for immunoglobulin chains or any known CD molecule. We conclude that monoclonal antibody NU-B1 recognizes a novel human B-cell restricted antigen distinct from known CD molecules, and that it is a useful antibody in the immunophenotyping and classification of leukemias/lymphomas.

Adult↗

Cellular mechanisms of renal adaptation of sodium dependent sulfate cotransport to altered dietary sulfate in rats.

The renal transport and fractional reabsorption of inorganic sulfate is altered under conditions of sulfate deficiency or excess. The objective of this study was to examine the cellular mechanisms of adaptation of renal sodium/sulfate cotransport after varying dietary intakes of a sulfur containing amino acid, methionine. Female Lewis rats were divided into four groups and fed diets containing various concentrations of methionine (0, 0.3, 0.82 and 2.46%) for 8 days. Urinary excretion rates and renal clearance of sulfate were significantly decreased in the animals fed a 0% methionine diet or a 0.3% methionine diet, and significantly increased in the animals fed a 2.46% methionine diet when evaluated on days 4 and 7. Serum sulfate concentrations were unchanged by diet treatment in all animals. The fractional reabsorption of sulfate was significantly increased in the animals fed the 0% methionine diet and the 0.3% methionine diets, and decreased in the animals fed the 2.46% methionine diet. Increased mRNA and protein levels for the sodium/sulfate transporter (NaSi-1) were found in the kidney cortex following treatment with the 0 and 0.3% methionine diet groups. Sulfate homeostasis by renal reabsorption is maintained by an up-regulation of steady state levels of NaSi-1 mRNA and protein when the diet is low in methionine.

Animals↗

Ibuprofen-induced changes in sulfate renal transport.

Nonsteroidal anti-inflammatory drugs (NSAIDs) increase sulfate renal clearance and decrease the fractional reabsorption of sulfate by the kidneys. The mechanism of this alteration of inorganic sulfate homeostasis is unknown. The objectives of this study were 1) to investigate if sulfate renal transport is altered in isolated membrane vesicles after pretreatment of animals in vivo with ibuprofen (IBU), and 2) to determine the cellular mechanism of changes in sulfate renal transport. Female Lewis rats received IBU at a i.v. dose of 27 mg/kg followed by an infusion of 33 microg/min for 4 hr. Sulfate transport was studied using brush border (BBM) and basolateral membrane (BLM) vesicles isolated from rat kidney cortex. The Vmax for the sodium-dependent sulfate cotransport (NaSi-1) in BBM was significantly lower in the IBU group compared with the control group (0.79 +/- 0.23 vs. 1.25 +/- 0.17 nmol/mg protein/10 sec, respectively; P <.05) with no change in Km. There were no significant differences between the study groups in sulfate anion exchange kinetics in BLM vesicles. NaSi-1 transporter mRNA level in kidney cortex and protein level in BBM were significantly lower in animals pretreated with IBU compared with that in control animals. There was no change in membrane fluidity of BBM and BLM isolated from IBU-treated animals as measured by the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene. These results indicate that IBU treatment alters sodium-dependent sulfate cotransport by a downregulation of mRNA and protein of NaSi-1 transporter in BBM.

Animals↗

The protein-tyrosine phosphatase SHP-2 associates with tyrosine-phosphorylated adhesion molecule PECAM-1 (CD31).

Aggregation of many cell-surface receptors results in tyrosine phosphorylation of numerous proteins. We previously observed the tyrosine phosphorylation of the platelet/endothelial cell adhesion molecule, PECAM-1 (CD31), after FcepsilonRI stimulation in rat basophilic leukemia RBL-2H3 cells. Here we found that PECAM-1 was also transiently tyrosine-phosphoryated after adherence of these cells to fibronectin. Similarly aggregation of the T cell receptor on Jurkat cells also induced this tyrosine phosphorylation. The protein-tyrosine phosphatase SHP-2 is a widely expressed cytosolic enzyme with two Src homology 2 (SH2) domains. SHP-2, but not the related protein-tyrosine phosphatase SHP-1, associated with PECAM-1. This association of the two proteins correlated with the extent of the tyrosine phosphorylation of PECAM-1. A fusion protein containing the two SH2 domains of SHP-2 precipitated PECAM-1 from cell lysates and also directly bound to phosphorylated PECAM-1. In immune precipitate phosphatase assays, there was tyrosine dephosphorylation of PECAM-1. Therefore, integrin and immune receptor activation results in tyrosine phosphorylation of PECAM-1 and the binding of the protein-tyrosine phosphatase SHP-2, which could regulate receptor-mediated signaling in cells.

Animals↗

Syk-independent tyrosine phosphorylation and association of the protein tyrosine phosphatases SHP-1 and SHP-2 with the high affinity IgE receptor.

Aggregation of the high affinity IgE receptor (Fc epsilonRI), a member of the immune receptor family, results in the activation of protein tyrosine kinases and downstream signaling pathways. The two cytoplasmic Src homology 2 domain-containing protein tyrosine phosphatases, SHP-1 (also called SH-PTP1, PTP1C or HCP) and SHP-2 (also known as SH-PTP2, PTP1D, PTP2C, or Syp), are expressed in the RBL-2H3 rat mast cell line. Here we report that aggregation of Fc epsilonRI induced the tyrosine phosphorylation of both SHP-1 and SHP-2. This phosphorylation was independent of the presence of the protein tyrosine kinase Syk. Both SHP-1 and SHP-2 associated with Fc epsilonRI. Whereas SHP-1 was constitutively associated with the receptor, SHP-2 coprecipitated with Fc epsilonRI only after receptor aggregation. Fusion proteins containing either the full-length or the Src homology 2 domains of SHP-2 directly bound to the tyrosine-phosphorylated beta, but not the gamma, subunit of Fc epsilonRI. In the reciprocal experiments, synthetic phosphorylated peptides based on the immunoreceptor tyrosine-based activation motif of the beta, but not the gamma, subunit precipitated SHP-2. In contrast, neither fusion proteins nor synthetic peptides detected interaction between SHP-1 and Fc epsilonRI. In vitro, both SHP-1 and SHP-2 dephosphorylated tyrosine-phosphorylated beta and gamma subunits of Fc epsilonRI. Therefore, SHP-1 and SHP-2 associate with Fc epsilonRI by different mechanisms and can regulate the extent of the tyrosine phosphorylation of the receptor subunits. Thus, unlike other immune cells in which inhibitory molecules are recruited by accessory proteins, Fc epsilonRI bind molecules that both activate and inhibit signal transduction.

Amino Acid Sequence↗

Aggregation of the high affinity IgE receptor results in the tyrosine phosphorylation of the surface adhesion protein PECAM-1 (CD31).

One of the earliest events after aggregation of the high affinity receptor for IgE (FcepsilonRI) on mast cells is the activation of protein tyrosine kinases resulting in tyrosine phosphorylation of numerous proteins. Using a monoclonal antibody raised against the rat basophilic leukemia RBL-2H3 cells, we identified that platelet/endothelial cell adhesion molecule 1 (PECAM-1 or CD31) was tyrosine phosphorylated in these cells. Aggregation of PECAM-1 did not induce a detectable increase in its tyrosine phosphorylation, nor did it result in degranulation. However, the minimal tyrosine phosphorylation of PECAM-1 in nonstimulated cells was dramatically increased after FcepsilonRI aggregation. This receptor-induced tyrosine phosphorylation of PECAM-1 was an early event, independent of Ca2+ influx or of the activation of protein kinase C and of cell adhesion. PECAM-1 is an adhesion molecule that is required for the transmigration of leukocytes across the endothelium into sites of inflammation. Therefore tyrosine phosphorylation of PECAM-1 may modulate its interaction with other molecules, thereby regulating the migration of basophils into inflammatory sites.

Animals↗

Increased expression of interleukin-2 receptor alpha on peripheral blood mononuclear cells in HTLV-I tax/rex mRNA-positive asymptomatic carriers.

Using the double-nested reverse transcription-polymerase chain reaction, we assayed human T-cell leukemia virus type I (HTLV-I) tax/rex-encoded mRNA in the peripheral blood mononuclear cells (PBMCs) of asymptomatic carriers as an index of the expression of HTLV-I in vivo in relation to the proviral DNA level. HTLV-I tax/rex mRNA was detected in only 1 (3.3%) of 30 samples with medium or lower proviral DNA levels, but it was detected in 11 (39.3%) of 28 samples with high HTLV-I proviral DNA levels, estimated as equal to or more than the proviral DNA of 10 ng of HUT102 (i.e., HUT102 cells were used as positive controls). The mean number of interleukin-2 receptor alpha (IL-2R alpha)-positive cells as a percentage of the total number of PBMCs was higher (13.2%) in the tax/rex mRNA-positive carriers with high proviral DNA levels than in the carriers who were mRNA negative (8.4%) (p = 0.004, Wilcoxon test). These results suggest that virus activation as indicated by the presence of tax/rex mRNA in asymptomatic carriers with high proviral DNA levels is associated with an elevation of the IL-2R alpha-positive cells in vivo.

Carrier State↗

Disopyramide concentrations in human plasma and saliva: comparison of disopyramide concentrations in saliva and plasma unbound concentrations.

OBJECTIVE: This study was performed to investigate whether it is possible to use saliva instead of blood usually used for therapeutic drug monitoring (TDM) of disopyramide. METHODS: Six healthy male volunteers ingested 200 mg of disopyramide base, and the disopyramide concentrations in saliva and plasma (total and unbound) were determined by the HPLC. RESULTS: Disopyramide concentration-time profiles for the saliva were nearly equal to those for the plasma unbound concentrations. A large variation for absorption time of the drug was observed among the subjects. Disopyramide concentrations (Cs) in saliva did not correlated well with plasma total concentrations (Cp), r = 0.799, but did well with unbound concentrations (Cpu), r = 0.969, for the 3-12 h period on the elimination phase. The mean ratio of disopyramide concentrations in the saliva against the plasma unbound concentrations was almost constant (1.02(0.10), CV = 9.7%) for the period. The pharmacokinetic parameters (tmax, t1/2, AUC, AUMC and MRT values) for disopyramide calculated from the saliva data were nearly equal to those from the unbound data. CONCLUSION: Disopyramide concentrations in saliva correlated well with plasma unbound concentrations on the elimination phase.

Adult↗

On an ambulance stretcher suspension concerned with the reduction of patient's blood pressure variation.

The design process and control of an ambulance stretcher suspension to reduce patient's blood pressure variation (BPV) is discussed. The BPV caused by applying the vehicle brakes may lead to deterioration of a patient's condition. The proposed method can reduce BPV by tilting the stretcher and counterbalancing back-to-front acceleration of the ambulance with gravity. The experimental results obtained when using a manually controlled stretcher confirm that BPV is reduced by tilting the stretcher. A continuous control method that varies the tilting angle is investigated through simulation analysis. The results show that this control method reduces the BPV effectively and achieves safe transport of the patient.

Acceleration↗