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Biomedical subjects

S Kurosawa

Publications and source records attributed to S Kurosawa.

At least 37 records · Page 2Linked to original sources
PubMed2000

Pheromonal and kairomonal activities can be separated: synthesis and bioactivity studies of pine bast scale sex pheromones and their analogues.

New syntheses were achieved to secure matsuone (1), the pheromone of the pine scale Matsucoccus matsumurae, that of M. feytaudi (2), and that of M. josephi (3). Five analogues (4-8) of 1, 2, and 3 were synthesized and their bioactivities studied. The pheromone analogue 7 showed relatively strong pheromonal activity toward M. josephi, while it was inactive as a kairomone toward the predator Elatophilus hebraicus. Similarly, analogue 8 acted as a pheromone for M. feytaudi, but it did not attract any of its local predators. The M. feytaudi pheromone 2 exhibited strong kairomonal activity toward E. hebraicus, but was not active as a pheromone mimic to attract M. josephi.

Animals↗
PubMed2000

The endothelial cell protein C receptor aids in host defense against Escherichia coli sepsis.

The influence of the endothelial protein C receptor (EPCR) on the host response to Escherichia coli was studied. Animals were treated with 4 separate protocols for survival studies and analysis of physiologic and biochemical parameters: (1) monoclonal antibody (mAb) that blocks protein C/activated protein C binding to EPCR plus sublethal numbers of E coli (SLEC) (n = 4); (2) mAb to EPCR that does not block binding plus SLEC (n = 3); (3) SLEC alone (n = 4); and (4) blocking mAB alone (n = 1). Those animals receiving blocking mAb to EPCR plus sublethal E coli died 7 to 54 hours after challenge, whereas all animals treated with the other protocols were permanent survivors. Histopathologic studies of tissues from animals receiving blocking mAb plus SLEC removed at postmortem were compared with those animals receiving SLEC alone killed at T+24 hours. The animals receiving the blocking mAb exhibited consumption of fibrinogen, microvascular thrombosis with hemorrhage of both the adrenal and renal cortex, and an intense influx of neutrophils into the adrenal, renal, and hepatic microvasculature, whereas the tissues from animals receiving only sublethal E coli exhibited none of these abnormal histopathologic changes. Compared with the control animals, the animals receiving the blocking mAb exhibited significantly elevated serum glutamic pyruvic transaminase, anion gap, thrombin-antithrombin complex, IL-6, IL-8, and soluble thrombomodulin. The levels of circulating activated protein C varied too widely to allow a clear determination of whether the extent of protein C activation was altered in vivo by blocking protein C binding to EPCR. We conclude that protein C/activated protein C binding to EPCR contributes to the negative regulation of the coagulopathic and inflammatory response to E coli and that EPCR provides an additional critical step in the host defense against E coli. (Blood. 2000;95:1680-1686)

Animals↗
PubMed2000

Plasma soluble interleukin-2 receptor levels during and after upper abdominal surgery.

Soluble interleukin-2 (IL-2) receptor (sIL-2R) is reported to be up-regulated in inflammatory disorders. Although sIL-2R may modulate perioperative inflammatory responses, it remains unclear whether upper abdominal surgery affects plasma sIL-2R levels. We evaluated the influence of major abdominal surgery on plasma sIL-2R levels. Ten patients scheduled for upper abdominal surgery received anaesthesia with isoflurane, nitrous oxide, and epidural block. Plasma sIL-2R and IL-6 levels were determined at pre-anaesthesia, 0, 2, and 4 hours during surgery, and on postoperative days 1 (POD1) and 3 (POD3). The plasma levels of sIL-2R decreased significantly and achieved their minimum value at 4 hours (677.0 +/- 125.3 pg/ml, P < 0.01 compared to pre-anaesthesia value; 924.5 +/- 178.8 pg/ml, 95% confidence interval = 122.2-550.4). The plasma sIL-2R levels increased on POD1 (1336.5 +/- 174.0 pg/ml) and POD3 (1629.0 +/- 262.8 pg/ml), and reached a level significantly higher than the baseline (P < 0.05 and P < 0.001, 95% confidence interval = 93.4-730.6 and 402.8-1006.2, respectively). The plasma sIL-2R levels on POD3 significantly correlated with the peak IL-6 levels (r = 0.67, P < 0.05). The plasma sIL-2R levels on POD3 correlated with the amount of intraoperative bleeding (r = 0.66, P < 0.05). In conclusion, we found that major abdominal surgery induces characteristic changes in plasma soluble IL-2 receptor levels.

Abdomen↗
PubMed2000

[Guideline for treatment of gastroesophageal reflux disease].

The endpoints should be settled before the treatment of GERD. These are symptom relief, healing and maintenance of erosive or ulcerative lesions, and also probably prevention of several complications of GERD. In medical treatment for GERD, we can take some different strategies, that is, single-agent, step-up or step-down therapy. The authors reviewed the effects of many drugs, being used for GERD therapy, and decided the levels of therapeutic effects from the view point of EBM. Using these results, we recommended that the therapy of GERD should be started with PPI of a regular dose and stepped-down in usual cases, but it should be begun with PPI and stepped-up in refractory cases. PPI may be necessary also for maintenance treatment in most latter cases. The guideline of the treatment for GERD were discussed.

Antacids↗
PubMed2000

[Maintenance therapy of mild form of GERD by H2 receptor antagonists].

Because of high relapse rate after the healing by proton pump inhibitor(PPI) or H2 receptor antagonist(H2RA), GERD usually needs long time maintenance therapy. PPI is superior to H2RA in the first line as well as maintenance therapy. PPI is necessary for severe cases of GERD. However, H2RA is sufficient for milder form of GERD patients. Among the H2RA using in Japan, nizatidine has known to stimulate gastric emptying and elevate LES pressure. Nizatidine may be superior to other H2RAs in the treatment of GERD. Recently, nocturnal acid breakthrough which night time acid is secreted even PPI is administered twice daily has been documented. H2RAs are stronger than PPI to inhibit nocturnal acid breakthrough and may be better than night time acid reflux.

Aged↗
PubMed1999

The effective removal of proinflammatory cytokines by continuous hemofiltration with a polymethylmethacrylate membrane following severe burn injury: report of three cases.

The serum levels of proinflammatory cytokines were investigated in three patients with severe burn injuries complicated by sepsis and pulmonary edema, who were treated with continuous hemofiltration (CHF) using a polymethylmethacrylate (PMMA) membrane. All patients had suffered burn injuries to more than 30% of their total body surface area (TBSA) and had burn indexes of 20 or more. Both interleukin (IL)-6 and tumor necrosis factor-alpha were detectable in one patient, while the serum IL-6 levels were elevated in the remaining two patients. The serum cytokines decreased 24 h after the initiation of CHF. Determinations of IL-6 in inflow and outflow blood samples as well as in the filtration fluid revealed that IL-6 was ultrafiltrated and/or adsorbed by the filter. Two of the three patients did not survive. Nevertheless, the results of this study indicate that since burn injuries are frequently associated with hypercytokinemia, the removal of cytokines by CHF with a PMMA membrane may be effective in the management of severe burn injuries.

Adult↗
PubMed1999

Photoinactivation of vesicular stomatitis virus with fullerene conjugated with methoxy polyethylene glycol amine.

Fullerene is known to effectively produce mainly singlet oxygen by absorbing light energy, and therefore may be useful as a virucidal photosensitizer. This study was designed to investigate the virucidal activity of a water-soluble fullerene derivative, which is conjugated with methoxy polyethylene glycol amine to enhance its water solubility. Vesicular stomatitis virus (VSV) was inactivated upon illumination with this water-soluble fullerene, in a concentration- or dose-dependent manner. The titer of VSV was reduced by >5log 10 in the presence of 10 mg/ml (400 microM) fullerene derivative with 120 J/cm2 white light irradiation. VSV inactivation was inhibited by oxygen removal or by the addition of sodium azide, a known singlet oxygen scavenger. The substitution of H2O by D2O, which is known to prolong the lifetime of singlet oxygen, promoted the virucidal activity. These results indicate that singlet oxygen may play a major role in VSV photoinactivation by the water-soluble fullerene derivative. The concentration needed for virus inactivation is higher than that of other sensitizers such as methylene blue.

Antiviral Agents↗
PubMed1999

Inflammation, sepsis, and coagulation.

The molecular links between inflammation and coagulation are unquestioned. Inflammation promotes coagulation by leading to intravascular tissue factor expression, eliciting the expression of leukocyte adhesion molecules on the intravascular cell surfaces, and down regulating the fibrinolytic and protein C anticoagulant pathways. Thrombin, in turn, can promote inflammatory responses. This creates a cycle that logically progresses to vascular injury as occurs in septic shock. Most complex systems are regulated by product inhibition. This inflammation-coagulation cycle seems to follow this same principle with the protein C pathway serving as the regulatory mechanism. The molecular basis by which the protein C pathway functions as an anticoagulant is relatively well established compared to the mechanisms involved in regulating inflammation. As one approach to identifying the mechanisms involved in regulating inflammation, we set out to identify novel receptors that could modulate the specificity of APC in a manner analogous to the mechanisms by which thrombomodulin modulates thrombin specificity. This approach led to the identification of an endothelial cell protein C receptor (EPCR). To understand the mechanism, we obtained a crystal structure of APC (lacking the Gla domain). The crystal structure reveals a deep groove in a location analogous to anion binding exosite 1 of thrombin, the location of interaction for thrombomodulin, platelet thrombin receptor and fibrinogen. Thrombomodulin blocks the activation of platelets and fibrinogen without blocking reactivity with chromogenic substrates or inhibitors. Similarly, in solution, EPCR blocks factor Va inactivation without modulating reactivity with protease inhibitors. Thus, these endothelial cell receptors for the protein C system share many properties in common including the ability to be modulated by inflammatory cytokines. Current studies seek to identify the substrate for the APC-EPCR complex as the next step in elucidating the mechanisms by which the protein C pathway modulates the response to injury and inflammation.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Regulation and functions of the protein C anticoagulant pathway.

The protein C pathway plays a critical role in the negative regulation of the blood clotting process. We recently identified an endothelial cell receptor for protein C/activated protein C (APC). The receptor is localized almost exclusively on endothelial cells of large vessels and is present at only trace levels or indeed absent from capillaries in most tissues. Patients with sepsis or lupus erythematosus exhibit elevated levels of plasma EPCR which migrates on gels as a single band and is fully capable of binding protein C/APC. There is no correlation with thrombomodulin levels, probably due to different vascular localizations and/or cellular release mechanisms. To understand the mechanisms by which EPCR plasma levels are elevated, we examined EPCR mRNA expression in a rat endotoxin shock model. The EPCR mRNA gene exhibited an early immediate gene response to endotoxin with the mRNA levels increasing nearly 4 fold in the first 3-6 hrs, before returning toward baseline. Plasma levels of EPCR also rose about 4 fold with little change in tissue EPCR levels. Both processes were markedly attenuated by hirudin suggesting that thrombin was responsible for increases in mRNA and plasma EPCR levels. At the level of mRNA, the induction is mediated by a thrombin response element in the 5' flanking region of the gene. Direct thrombin infusion and cell culture experiments support this contention. On endothelium, thrombin is capable of releasing cell surface EPCR and this process is blocked by the metalloproteinase inhibitor orthophenanthroline. Taken together these studies indicate that elevation in soluble plasma EPCR reflects endothelial cell activation in the larger vessels and is likely to be an indication of local thrombin generation near these vessel surfaces.

Animals↗
PubMed1998

A chimeric protein C containing the prothrombin Gla domain exhibits increased anticoagulant activity and altered phospholipid specificity.

To determine the structural basis of phosphatidylethanolamine (PE)-dependent activated protein C (APC) activity, we prepared a chimeric molecule in which the Gla domain and hydrophobic stack of protein C were replaced with the corresponding region of prothrombin. APC inactivation of factor Va was enhanced 10-20-fold by PE. Protein S enhanced inactivation 2-fold and independently of PE. PE and protein S had little effect on the activity of the chimera. Factor Va inactivation by APC was approximately 5-fold less efficient than with the chimera on vesicles lacking PE and slightly more efficient on vesicles containing PE. The cleavage patterns of factor Va by APC and the chimera were similar, and PE enhanced the rate of Arg506 and Arg306 cleavage by APC but not the chimera. APC and the chimera bound to phosphatidylserine:phosphatidylcholine vesicles with similar affinity (Kd approximately 500 nM), and PE increased affinity 2-3-fold. Factor Va and protein S synergistically increased the affinity of APC on vesicles without PE to 140 nM and with PE to 14 nM, but they were less effective in enhancing chimera binding to either vesicle. In a factor Xa one-stage plasma clotting assay, the chimera had approximately 5 times more anticoagulant activity than APC on PE-containing vesicles. Unlike APC, which showed a 10 fold dependence on protein S, the chimera was insensitive to protein S. To map the site of the PE and protein S dependence further, we prepared a chimera in which residues 1-22 were derived from prothrombin and the remainder were derived from protein C. This protein exhibited PE and protein S dependence. Thus, these special properties of the protein C Gla domain are resident outside of the region normally hypothesized to be critical for membrane interaction. We conclude that the protein C Gla domain possesses unique properties allowing synergistic interaction with factor Va and protein S on PE-containing membranes.

Amino Acid Sequence↗
PubMed1998

Systemic hypotensive response to protamine following chronic inhibition of nitric oxide synthase in rats.

PURPOSE: The aims of the present studies were to determine whether the systemic hypotensive response to protamine was modified in rats pre-treated for two weeks with the nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl ester (L-NAME), and to evaluate the inhibitory effect of heparin on the systemic hypotensive response to protamine in vivo. METHODS: Male rats were randomly assigned into four groups. Normal saline 12 microliters.day-1, D-NAME (an inactive enantiomer of L-NAME), 10 mg.kg-1, L-NAME, 1 or 10 mg.kg-1.day-1 i.p. was administered for two weeks and the haemodynamic changes were measured after protamine administration. In another experiment, male rats were assigned to two groups. In one, the heparin group, protamine was administered after heparin had been administered and in the other, protamine group, protamine alone was administered. RESULTS: L-NAME inhibited the decrease in systemic arterial pressure after protamine administration (P < 0.05), but D-NAME had no effect. Also, heparin reduced the decrease in systemic arterial pressure after protamine (P < 0.05). CONCLUSION: Nitric oxide is mainly responsible for mediation of the systemic hypotensive response to protamine which is also reduced by heparin.

Analysis of Variance↗
PubMed1998

[The effects of midazolam on the memory of pain].

The purpose of this study was to evaluate the effects of low dose midazolam (MZ) on memories of spinal puncture. The low doses of MZ were administered to 70 patients (ASA 1-2), of whom 37 patients were premedicated with atropine sulfate 0.5 mg and pethidine hydrochloride i.m. (group P), and 33 patients received no premedication (group N). Double blind randomized trials were conducted with the doses of MZ (0, 0.03, 0.06 mg.kg-1), and MZ was administered i.v. to the patients just prior to spinal puncture. Subjective evaluation of pain was performed with pain score (PS) on postoperative phase, and objective evaluation of pain was performed with the reaction of spinal puncture. Short term memory was impaired mainly after administration of MZ. However, subjective memory of pain almost disappeared, but objective evaluation was not so good. We conclude that MZ induces impairment to recall of pain. However, it might maintain the response to the pain.

Adjuvants, Anesthesia↗
PubMed1998

[Evaluation of risks for postoperative pulmonary complications using a preoperative consultation system].

We retrospectively investigated the perioperative management and postoperative pulmonary complications of patients who had preoperative respiratory problems and consultations with anesthesiologists. These patients numbered eight hundred, 23.7% of all patients who had preoperative consultations, and 40.9% and 62.0% of the 800 had preoperative and postoperative respiratory management, respectively. Forty eight patients (6.0%) received postoperative artificial respiration. One hundred and twenty four patients (15.5%) had some respiratory complications post-operatively, and 5 patients (0.7%) died mainly because of the complications. In an evaluation of these patients with the modified predicted risk factors of Okutsu including the obesity factor and smoking history, there was no respiratory complication in patients under 14 points. Patients with high points of more than 20 included almost all of the patients (114 patients, 91.9%) who had postoperative respiratory complications. We conclude that our preoperative consultation system works well and that the modified predicted-risk factors for postoperative pulmonary complications is useful for the standardization and objectivity of preoperative patient evaluation.

Humans↗
PubMed1998

[Bleeding in chronic refractory peptic ulcer].

The authors reviewed the clinical problems of the bleeding in refractory ulcers. Incidence of refractory and easily-relapsing ulcers are about 40% of all chronic ulcers and their bleeding rate seemed to be more than 10% of them. We discussed the relationship between bleeding and risk factors such as age, NSAID use, H. pylori infection, etc. The consideration to them is very important in the present time, being difficult to predict ulcer bleeding.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Identification of functional endothelial protein C receptor in human plasma.

The endothelial cell protein C receptor (EPCR) binds protein C and facilitates activation by the thrombin-thrombomodulin complex. EPCR also binds activated protein C (APC) and inhibits APC anticoagulant activity. In this study, we detected a soluble form of EPCR in normal human plasma. Plasma EPCR appears to be approximately 43, 000 D, and circulates at approximately 100 ng/ml (98.4+/-27.8 ng/ml, n = 22). Plasma EPCR was purified from human citrated plasma using ion exchange, immunoaffinity, and protein C affinity chromatography. Flow cytometry experiments demonstrated that plasma EPCR bound APC with an affinity similar to that previously determined for recombinant soluble EPCR (Kdapp = 30 nM). Furthermore, plasma EPCR inhibited both protein C activation on an endothelial cell line and APC anticoagulant activity in a one-stage Factor Xa clotting assay. The physiological function of plasma EPCR is uncertain, but if the local concentrations are sufficiently high, particularly in disease states, the present data suggest that the soluble plasma EPCR could attenuate the membrane-bound EPCR augmentation of protein C activation and the anticoagulant function of APC.

Anticoagulants↗