Inhibitory effects of propofol on intracellular signaling by endothelin-1 in aortic smooth muscle cells

BACKGROUND

Blood pressure decreases when propofol is administered. However, the exact mechanism underlying the vascular effects of propofol has not yet been elucidated. Endothelin produced by vascular endothelial cells is a potent vasoactive peptide that elicits prolonged contraction of vascular smooth muscle cells. The effects of propofol on endothelin-1-induced intracellular signaling in an aortic smooth muscle cell line, A10 cells, were examined.

METHODS

Cultured A10 cells were pretreated with propofol for 20 min and then stimulated with endothelin-1. The effect of propofol on the endothelin-1-induced Ca2+ influx into A10 cells was evaluated by measuring intracellular 45Ca2+. The effects of propofol on the endothelin-1-induced activation of phosphatidylinositol-hydrolyzing phospholipase C and phosphatidylcholine-hydrolyzing phospholipase D were evaluated by measuring the formation of inositol phosphates and choline, respectively. The effect of propofol on endothelin-1 binding to its receptor was determined by an [125I] endothelin-1-binding assay.

RESULTS

Propofol inhibited the endothelin-1-induced Ca2+ influx, but this was significant only at supuraclinical concentrations. The endothelin-1-stimulated formation of inositol phosphates was significantly suppressed by propofol. However, propofol had no effect on the formation of inositol phosphates induced by NaF, an activator of heterotrimeric guanosine triphosphate (GTP)-binding proteins. Propofol inhibited the endothelin-1-induced formation of choline. Propofol had no effect on the binding of endothelin-1 to its receptor.

CONCLUSIONS

These results suggest that propofol inhibits endothelin-1-induced intracellular signaling in vascular smooth muscle cells. The inhibitory effect of propofol might be exerted at a point between the endothelin-1 receptor and its GTP-binding protein. However, because all significant effects are observed at high concentrations, clinical relevance is unclear.

Long-term results of ABO-incompatible living kidney transplantation: a single-center experience

BACKGROUND

Despite great efforts to promote the donation of cadaveric organs, the number of organ transplantations in Japan is not increasing and a serious shortage of cadaveric organs exists. These circumstances have forced a widening of indications for kidney transplantation. For this purpose, ABO-incompatible living kidney transplantations (LKTs) have been performed. Although we have already reported the short-term results of ABO-incompatible LKT, there is no report of long-term results in such cases; anti-A and anti-B antibodies could cause antibody-induced chronic rejection and result in poor long-term graft survival. In this study, we have reviewed the long-term results of ABO-incompatible LKT and tried to identify the most important factors for long-term renal function in ABO-incompatible LKT.

METHODS

Sixty-seven patients with end-stage renal failure underwent ABO-incompatible living kidney transplantation at our institute between January, 1989, and December, 1995. The mean age was 34.9 years (range, 8-58 years), with 38 males and 29 females. Incompatibility in ABO blood group antigens was as follows: A1-->O, 23 patients; B-->O, 19 patients; A1B-->A1, 7 patients; B-->A1, 8 patients; A1-->B; 4 patients; A1B-->B, 4 patients; A1B-->O, 2 patients. The number of HLA-AB, and -DR mismatches were 1.6+/-1.1 and 0.76+/-0.6, respectively. Plasmapheresis and immunoadsorption were carried out to remove the anti-AB antibodies before the kidney transplantation. In the induction phase, methylprednisolone, cyclosporine, azathioprine, antilymphocyte globulin, and deoxyspergualin were used for immunosuppression. Local irradiation of the graft was performed at a dose of 150 rad, on the first, third, and fifth days after transplantation. Splenectomy was done at the time of kidney transplantation in all cases.

RESULTS

Patient survival was 93% at 1 year and 91% at 8 years. Graft survival was 79% at 1, 2, 3, and 4 years, 75% at 5 and 6 years, and 73% at 7 and 8 years. Patient survival was not significantly different from that of ABO-compatible patients. However, graft survival was significantly different between ABO-incompatible grafts and ABO-compatible grafts. Specifically, ABO-incompatible transplant recipients experienced a significantly higher rate of early graft loss up to 3 years but showed an equivalent graft loss by year 4. Among 67 patients, 16 grafts were lost during the observation period. Loss was due to acute rejection in 5 patients, followed by chronic rejection in 5 patients and death with function in 3 patients, whereas immunosuppression was withdrawn in 3 patients due to nonimmunological reasons. Of 16 grafts lost, 15 were lost within 1 year after transplantation. Of the 67 patients, 5 died during observation. Three patients with functioning grafts died of uncontrolled bleeding due to duodenal ulcer, malignant lymphoma, and cerebral hemorrhage (one patient each). One patient died of ischemic colitis due to secondary amyloidosis and one patient of cerebral hemorrhage after graft loss due to humoral rejection. There was no fatal infectious complication, whereas 10 patients had non-tissue-invasive cytomegalovirus infection. The stepwise logistic regression model was employed to identify the most important factors for long-term renal function. Patients were subdivided into those with serum creatinine of less than 2.0 mg/dl (group 1, n=39) versus those with serum creatinine of more than 2.0 mg/dl (group 2, n=22) at one year after renal transplantation. Six patients were excluded because of death with functioning graft (three patients) and withdrawal of immunosuppression (three patients). Rejection episodes within 6 months were significantly frequent in group 2 compared with group 1 (P=0.0008). Odds ratio was 112-fold in the rejection episodes. Obviously, the high incidence of early humoral rejection is caused by ABO incompatibility, because ABO-incompatible grafts experience a higher rate of early rejection and graft loss compa

Retroviral transduction of intercellular adhesion molecule-1 enhances endothelial attachment of bladder cancer

An intercellular adhesion molecule-1 (ICAM-1)-negative RT4 transitional cell carcinoma (TCC) cell line was transduced with full-length ICAM-1 cDNA via a retroviral vector. Flow cytometry showed that a sense-oriented clone (S20) highly expressed ICAM-1 while an anti-sense clone (AS6) did not. Both S20 and AS6 bound with equal frequency (30 +/- 8.7% vs 30 +/- 9.4%) to unstimulated human umbilical vein endothelial cells (HUVECs) in cell attachment assays. However, when phorbol myristate acetate (PMA)-activated T lymphocytes, which express lymphocyte function-associated antigen-1 (LFA-1), were cocultured with tumor cells, attachment of S20 increased twofold (60 +/- 11.9%) but AS6 showed no change (32 +/- 11%). Blocking studies with anti-LFA-1 and anti-ICAM-1 monoclonal antibodies caused an inhibition of the attachment to baseline levels, demonstrating that the enhancement of S20 attachment was dependent upon the LFA-1/ICAM-1 interaction. Enhanced attachment of S20 was not inhibited by the addition of isotypic immunoglobulin G. These results suggest that LFA-1-expressing leukocytes may act as a bridge between the endothelium and tumor cells which express ICAM-1 and, thereby, enhance the potential for hematogenous metastasis.

Stable patterns of allelic diversity at the Merozoite surface protein-1 locus of Plasmodium falciparum in clinical isolates from southern Vietnam

The extent of allelic diversity at the Merozoite Surface Protein-1 locus of Plasmodium falciparum (PfMSP-1) was examined in isolates collected from symptomatic patients living in a mesoendemic area in southern Vietnam. The variable blocks 2, 4 and 10 were typed by polymerase chain reaction and 24 PfMSP-1 gene types were defined as unique combinations of allelic types detected in each variable block. Nineteen PfMSP-1 gene types were identified and 182 parasite populations were fully typed among 102 isolates. Forty-eight (47%) patients harbored more than one typed parasite population, and one patient had at least eight genetically distinct subpopulations. As previously shown in the same endemic area, recombination between blocks 4 and 10 was significantly less frequent than expected from random assortment of allelic types. The distribution of PfMSP-1 gene types, however, did not differ significantly from that observed in isolates collected in the same area 17-24 mo before the present study. Furthermore, the prevalence of the most common gene types and the average number of different gene types harbored by the same host did not decrease with age. This argues against the prominence of frequency-dependent immune selection of PfMSP-1 polymorphisms in this parasite population.

Alternative expression of Shc family members in nerve-injured motoneurons

Expression of Shc family protein (Shc/ShcA, SCK/ShcB and N-Shc/ShcC) and Grb2 mRNAs in the hypoglossal motoneurons after axotomy was examined by in situ hybridization. In normal hypoglossal motor neurons, N-Shc mRNA was expressed predominantly, whereas the Shc mRNA level is very low. Rat hypoglossal nerve injury reversed the expressions of these two molecules in hypoglossal motoneurons. Shc mRNA expression was up-regulated markedly whereas N-Shc was down-regulated after nerve injury. Expression levels of SCK, another Shc family member, and Grb2 were unaffected by nerve injury. These results suggest that, whereas the N-Shc-mediated pathway dominates under normal conditions, an alternative Shc-mediated pathway is utilized in the event of nerve injury. By changing the expression of the Shc family members, the signaling pathway can be altered and various responses induced for nerve regeneration.

Leptin induces proliferation of pancreatic beta cell line MIN6 through activation of mitogen-activated protein kinase

Leptin at 1-5 nM, the concentrations observed in obese subjects, caused an increase in the active form of mitogen-activated protein kinase (MAPK) that was accompanied by increased tyrosine phosphorylation of STAT-1 and STAT-3 in a mouse pancreatic beta cell line, MIN6. Leptin also increased DNA synthesis and cell viability in MIN6 cells based on the results of [3H]-thymidine incorporation and colorimetric MTT assay, respectively. The specific MAPK-inhibitor PD98059 blocked not only the MAPK activation but also the increment in DNA synthesis and cell viability caused by leptin. Thus, leptin stimulates both the MAPK and the Janus kinase (JAK)-STAT cascade as well as inducing proliferation through the MAPK cascade in MIN6 cells. This mechanism might account, at least in part, for obesity-induced pancreatic islet hypertrophy.

Comparative study of cytomegalovirus (CMV) antigenemia assay, polymerase chain reaction, serology, and shell vial assay in the early diagnosis and monitoring of CMV infection after renal transplantation

BACKGROUND

Early diagnosis of cytomegalovirus (CMV) infection, which is an important cause of morbidity and mortality in renal transplant recipients, remains of great importance. This prospective study was performed in kidney transplant recipients to determine the diagnostic value of the CMV antigenemia assay in comparison with polymerase chain reaction (PCR), serology, and shell vial assay.

METHODS

Seventy-five consecutive renal transplant recipients were enrolled in this study and monitored by both antigenemia assay and serology. The initial 34 of the 75 patients were subjected to PCR and shell vial assay.

RESULTS

Antigenemia, PCR, and shell vial assay became positive before the onset of CMV-related symptoms in 31/34 (89%), 13/16 (81%), and 2/16 (13%), respectively. None of the 34 patients who had symptomatic CMV disease showed a significant increase in IgG or IgM before the onset of symptoms. Antigenemia and PCR assays turned positive, 7 and 11 days (median), respectively, before the onset of clinical symptoms. Serology and shell vial assay became positive 21 and 25 days (median), respectively, after the onset of CMV-related clinical symptoms. To examine the clinical value of these assays, "good correlation" was defined based on the correlation between the clinical course and the results of the assays. Good correlation with the antigenemia assay was observed in 33 (96%) out of 34 renal transplant recipients who recovered from their CMV disease after ganciclovir therapy. Only one of 16 (7%) patients showed good correlation by shell vial assay, whereas PCR and serology did not show a good correlation. Consequently, antigenemia was considered the best way to monitor CMV infections after kidney transplantation.

CONCLUSIONS

Only the CMV antigenemia assay can be successfully employed after renal transplantation for the early diagnosis and extensive monitoring of active CMV infection.

[Mechanism of increase in exercise tolerance in patients with acute myocardial infarction]

The contribution of cardiac output reserve and the skeletal muscle to exercise capacity was investigated in 24 patients with acute myocardial infarction. Symptom-limited exercise tests with a cycle ergometer were performed at 1 week, 3 weeks, and 3 months after the onset of the first infarction. Ventilatory gas was analyzed throughout the testing, and peak oxygen uptake (peak VO2) and anaerobic threshold (AT) were determined. During the test, the cardiac index (CI) was measured by the dye dilution method and the change in CI during exercise (delta CI) was calculated as an index of cardiac output reserve. The cross-sectional area of the thigh muscles (CSA) at the level of 10 cm above the patella was measured using computed tomography. Peak VO2 and AT increased significantly from 1 week to 3 months after the onset of infarction. delta CI increased significantly from 1 week to 3 weeks, and CSA increased significantly from 3 weeks to 3 months. Peak VO2 correlated significantly with both delta CI and CSA at each measurement point, as was AT with delta CI and CSA. Change in peak VO2 correlated with change of delta CI from 1 week to 3 weeks, and also with both delta CI and CSA from 3 weeks to 3 months. These results suggest that both cardiac output reserve and peripheral factors contribute to the exercise capacity up to 3 months after the onset of myocardial infarction. In particular, peripheral factors such as muscle volume are important to improve exercise capacity from 3 weeks to 3 months.

Antithrombotic and hemorrhagic effects of DX-9065a, a direct and selective factor Xa inhibitor: comparison with a direct thrombin inhibitor and antithrombin III-dependent anticoagulants

(+)-2S-2-[4-[[(3S)-1-Acetimidoyl-3- pyrrolidinyl]oxy]phenyl]-3-[7-amidino-2-naphthyl]propanoic acid hydrochloride pentahydrate (DX-9065a) is an antithrombin III (AT III)-independent and selective inhibitor of activated blood coagulation factor X (FXa). The aim of the present study was to compare the antithrombotic and hemorrhagic effects of DX-9065a with a direct thrombin inhibitor and AT III-dependent anticoagulants in rat models of thrombosis and bleeding. Rats were administered intravenously DX-9065a (0.1-1 mg/kg/h), argatroban (0.1-1 mg/k/h), low molecular weight heparin (25-100 anti-XaU/kg/h), unfractionated heparin (25-100 anti-XaU/kg/h) or Orgaran (30-300 anti-XaU/kg/h) for 1 h. DX-9065a dose-dependently inhibited both thrombus formation and elevation in plasma thrombin-AT III complex (TAT) level in a copper wire-inserted arteriovenous (AV) shunt model in rats. The dose required for 50% inhibition of thrombus formation was 0.27 mg/kg/h. DX-9065a did not prolong transection bleeding time up to 7.78 mg/kg/h. Argatroban and AT III-dependent anticoagulants also inhibited both thrombus formation and TAT elevation, but prolonged bleeding time at a slightly higher dose than the effective dose. These results suggest that direct and selective inhibition of factor Xa by DX-9065a is preferable for the treatment of thrombosis in the aspect of lack of compromising primary hemostasis.

Long-term outcome of renal transplantation in hepatitis B surface antigen-positive patients in cyclosporin era

The impact of hepatitis B virus (HBV) infection on the outcome of renal transplantation (Tx) has been controversial. To determine the indication of renal Tx in patients infected by HBV, we investigated the long-term outcome of renal transplant patients with hepatitis B surface antigen (HBsAg). We analyzed 980 patients, including 18 HBsAg carriers, who underwent renal Tx and were immunosuppressed with cyclosporin in our institute. Fourteen out of 18 patients (77.8%) showed hepatic dysfunction after an average period of 17.8 months (range 1-65) after Tx. Four out of 14 patients (28.5%) with hepatic dysfunction died of liver failure due to fulminant hepatitis with functioning grafts between 15 and 71 months after Tx. The remaining 10 patients with hepatic dysfunction are alive up to the time of last follow-up; however, 5 of them lost their grafts because of rejection between 44 and 92 months after Tx. Their liver function improved after withdrawal of cyclosporin. Only 4 patients did not develop chronic liver disease and have had functioning grafts for between 44 and 147 months. One patient died of subarachnoid hemorrhage 22 months after Tx. HBe antigen, antibody and HCV antibody status were not related to the occurrence of liver dysfunction after Tx. Four HBV-DNA-positive patients showed deteriorated liver function. Three patients with chronic active hepatitis confirmed by the biopsy were treated with interferon. Interferon improved liver function in 2 patients, however, 1 patient died of liver failure despite interferon therapy. Our data suggested that the presence of HBsAg is often associated with chronic liver disease leading to liver failure regardless of HBe and HCV status after Tx. The indication of renal Tx in patients with HBsAg should be determined carefully giving consideration to these results.

Multiple schwannomas in the radial nerve

We present a case of multiple schwannomas in the radial nerve. The occurrence of multiple schwannomas in a single major nerve is very rare. Magnetic resonance imaging was useful in detecting the tumours. As schwannomas may be multiple without clinical symptoms, we recommend MR imaging of the entire limb when schwannomas occur in a major nerve in the upper extremity.

Investigation of the adducts formed by reaction of butenedioic acids with adenosine

Several genotoxic butenedioic acids present in chlorine-disinfected drinking water were allowed to react with adenosine, guanosine, and cytidine in aqueous solution. HPLC analyses, with detection at 254 and 310 nm, showed that clearly detectable products were formed only in the reactions with adenosine. The major products from the reactions between either 2-chloro-3-methyl-2-butenedioic acid (ox-MCF) or 2-chloro-3-(chloromethyl)-2-butenedioic acid (ox-CMCF) and adenosine were the same. This substance was isolated by C18 column chromatography and characterized by UV absorbance, 1H and 13C NMR spectroscopy, and mass spectrometry. It was identified as 3-(beta-D-ribofuranosyl)-7-carboxy-7-formyl-8-[9'-(beta-D-ribofuranosyl) -N6- adenosinyl]-1,N6-ethanoadenosine (cf epsilon A,A). The yields of cf epsilon A,A in reactions performed at pH 7.4 and 37 degrees C were 0.7% and 0.3% with ox-MCF and ox-CMCF, respectively.

Ethanol sclerosis: one of the best treatments for thymic cyst in very elderly patients?

An 83-year-old female patient with a giant thymic cyst that was successfully treated by percutaneous aspiration and ethanol injection. The patient had complained of coughing and chest discomfort for several years. A chest X-ray film revealed the shadow of a large abnormal mass in the anterior mediastinum. We diagnosed it as a thymic cyst. The patient refused surgery because of her age. We chose a less invasive therapy, namely, ethanol sclerosis of the cyst. The cyst was successfully treated without any complications, and no recurrence was found at the one-year follow-up. This therapy may be one of the best treatments for thymic cysts, especially in very elderly patients.

Epitope analysis of human T-cell response to MSP-1 of Plasmodium falciparum in malaria-nonexposed individuals

BACKGROUND

MSP-1 of Plasmodium falciparum induces strong proliferative T cell responses even in malaria-nonexposed individuals. Epitopes recognized by malaria-nonimmune T cells have not been identified, and immunological mechanisms inducing such T cell responses remain to be uncovered. MSP-1 is a vaccine candidate, and it should be understood whether those epitopes have any roles in MSP-1-mediated protective immunity. The T epitopes-inducing malaria-naive T cell response was analyzed in the hope of understanding the underlying mechanisms.

METHODS

Human T cell lines and clones reactive to MSP-1 of P. falciparum were established from malaria-nonexposed Japanese donors in vitro, and epitope peptides were identified. Sequences of those epitope peptides were compared to unrelated peptides in the data base. One of those peptides was tested for both binding to HLA-DR molecules and inducing proliferative responses of MSP-1-reactive T cells.

RESULTS

There are at least 6 epitopes recognized by malaria-naive T cells under the restriction by HLA-DRB1*1502 or 0802. Important amino acids for the T cell recognition were identified for an MSP-1 peptide. A yeast peptide which shared those residues induced proliferative responses of MSP-1-reactive T cells.

CONCLUSION

We identified T epitopes in the N-terminal region of MSP-1, some of which showed molecular similarities with unrelated environmental antigens, suggesting the presence of cross-reactive T epitopes in MSP-1. Cytokine production in response to those epitopes suggests regulatory functions of those T cells during primary infection with P. falciparum.

[A case of a premenopausal woman with advanced breast cancer treated with aromatization inhibition in combination with luteinizing hormone-releasing hormone agonist]

A 44-year-old premenopausal woman having local recurrence and pleural and bone metastases of breast cancer was treated with aromatization inhibition in combination with Luteinizing Hormone-releasing Hormone (LH-RH) agonist. The dominant site of metastasis was a painful local lesion invading the chest wall. A partial response by reducing the size of the local lesion was attained 3 months after initiation of treatment. This result suggested that treatment using aromatization inhibition in combination with LH-RH agonist would be effective in premenopausal breast cancer. To confirm the effectiveness of this treatment, comparative study between aromatization inhibition in combination with LH-RH agonist aromatization inhibition alone and anti-estrogen in combination with LH-RH agonist are needed.

A new Thermus-Escherichia coli shuttle integration vector system

We established a Thermus thermophilus strain in which the pyrE gene (coding for orotate phosphoribosyltransferase of the pyrimidine biosynthetic pathway) was totally deleted. We also constructed an integration vector, which consisted of the Escherichia coli plasmid vector pBluescript and a 2.1-kb segment of the T. thermophilus leu operon sequence, for the integration of a foreign gene into a chromosome of the thermophile. pyrE and leuB genes were used as probes to test the integration vector. The integration vector pINV, bearing the pyrE gene, transformed the delta pyrE strain at a frequency of 6 x 10(-5) through a single crossover event. The leuB gene could also be used as another marker of the integration vector system. The vector could be integrated at the expected site. By digesting the chromosomal DNA of the T. thermophilus transformants with a unique restriction enzyme, the vector could be recovered into E. coli after the recircularization in vitro. The kanamycin nucleotidyltransferase gene could be successfully expressed in the thermophile by using pINV.

Relationship between progressive microvascular damage and intramyocardial hemorrhage in patients with reperfused anterior myocardial infarction: myocardial contrast echocardiographic study

BACKGROUND

Recent studies indicated that ischemic microvascular damage may be reversible or progressive after coronary reflow. Intramyocardial hemorrhage is a phenomenon that reflects severe microvascular injury. We examined the relationship between temporal changes in microvascular perfusion patterns detected by myocardial contrast echocardiography (MCE) and intramyocardial hemorrhage detected by magnetic resonance imaging (MRI) in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

The study population consisted of 24 patients with anterior AMI. All patients underwent MCE shortly after reflow and in the chronic stage (a mean of 31 days after reflow). Wall motion score (WMS) was determined as the sum of 16 segmental scores (dyskinetic/akinetic=3 to normal=0) at days 1 and 31. Gradient-echo acquisition and gadolinium-DTPA-enhanced spin-echo MRI were performed within 10 days after reflow. In MCE shortly after reflow, 16 patients (67%) showed contrast enhancement and the other 8 patients (33%) showed a sizable contrast defect. In the chronic stage, a persistent contrast defect was observed in 7 of 8 patients with a contrast defect shortly after reflow. Consistent contrast enhancement was observed in 12 of 16 patients (75%) with contrast enhancement shortly after reflow, indicating that a contrast defect newly appeared in 4 patients (25%). Intramyocardial hemorrhage was detected in 9 patients (38%): 5 of 7 patients with a persistent contrast defect and in all 4 patients with a new appearance of a contrast defect during the chronic stage. The patients without hemorrhage showed a significant improvement in WMS compared with patients with hemorrhage at day 31 (5+/-5 versus 19+/-6, P<.0005).

CONCLUSIONS

These results suggest that irreversible microvascular damage to the ischemic myocardium may cause intramyocardial hemorrhage after reflow, associated with impaired recovery of left ventricular function. Contrast enhancement within the risk area shortly after reflow does not necessarily indicate long-term microvascular salvage.

Diamond beam-position monitor for undulator radiation and tests at the Tristan Super Light Facility

A photon beam-position monitor using a diamond foil as a position-sensitive device has been developed for use on insertion-device beamlines of third-generation synchrotron radiation facilities such as SPring-8, and was tested on the undulator beamline of the Tristan Super Light Facility at KEK. The beam test results show that the diamond monitor can be operated in a photoconductive mode like a semiconductor detector. It has a linear working range of about +/-1 mm and a position sensitivity of less than 3 mum. The stability of the monitor was confirmed by continuous operation under low photon beam intensity conditions.

Postoperative production of anti-donor antibody and chronic rejection in renal transplantation

To study the relevance of anti-donor antibody (ADA) to chronic rejection in kidney transplantation, we retrospectively examined the long-term kinetics of ADA by flow cytometric analysis. Among 537 recipients who underwent living-donor kidney transplantation between 1986 and 1994, 29 patients with chronic rejection (CR group) and 33 patients with stable graft function (ST group) were randomly selected for analysis. Patient serum taken 1 or 2 days before transplantation, serum taken 1 month after transplantation, and the most current serum were analyzed for the presence of ADA to donor T and B cells. In the CR group, IgG antibody to donor B cells of the most current serum was positive in 25 of 29 patients, whereas it was positive in only 5 patients in the ST group P<0.001. The mean fluorescent intensity of the antibody was also significantly higher in the CR group than that in ST group P<0.01. In contrast, IgG antibody to donor T cells of the most current serum was positive in only five patients in the CR group. No significant difference was observed in the pretransplant and 1-month posttransplant sera between the CR and ST groups. We conclude that the posttransplant production of IgG antibody to donor B cells seemed to be highly relevant to chronic rejection.

[Factors affecting exercise capacity after coronary bypass grafting]

In order to determine the contribution of cardiac reserve and the peripheral muscle to exercise capacity in patients after Coronary Artery Bypass Grafting (CABG), 19 patients (18 males, 1 female, mean age 63.3 +/- 7.1 years, mean numbers of grafting 2.5 +/- 0.8) performed exercise tests at 1 week, 3 weeks, and 3 months after CABG. Ventilatory gas was analyzed throughout the testing and anaerobic threshold (AT) and peak oxygen uptake (peak VO2) was determined. During exercise testing, the cardiac index (CI) was measured, and the change in CI during exercise, delta CI = (CI at peak exercise) (CI at rest), was calculated. O2 delivery was derived from the product of CO and the oxygen content of arterial blood at peak exercise. The sectional area of the thigh muscles at the level of 10 cm above the patella was measured using a computed tomography before each test. Average peak VO2 at 1 week after CABG was 867 +/- 171 ml/min and it increased to 1,214 +/- 246 ml/min at 6 months. Average AT did not change from 1 week to 3 weeks, however, it increased significantly from 665 +/- 122 ml/min at 3 weeks to 873 +/- 181 ml/min at 6 months. The muscle area of the thigh increased significantly from 170 +/- 24 cm2 at 3 weeks after CABG to 186 +/- 27 cm2 at 3 months. delta CI showed a tendency to increase from 6.6 +/- 1.2 l/min/m2 at 1 week after CABG to 7.3 +/- 1.3 l/min/m2 at 3 weeks, and also showed a tendency to increase from 3 weeks to 6 months. Peak VO2 and AT correlated to delta CI at 1 weeks and also it correlated significantly to both the muscle area of the thigh and delta CI at 3 weeks, 3 months, and 6 months after CABG. The delta value of peak VO2 from 1 week to 3 weeks showed a significant correlation to those of delta CI and O2 delivery. Moreover, the delta values of peak VO2 and AT from 3 weeks to 3 months showed a correlation to those of delta CI and O2 delivery. These results suggest that both cardiac reserve and peripheral factors contribute to the exercise capacity up to 3 months after CABG, and, in particular, O2 delivery are important to increase exercise capacity.

[Validity and reliability of the Children's Health Locus of Control Scale]

The Multidimensional Health Locus of Control (MHLC) scales have been widely used as a measurement of health beliefs in child populations. Studies were conducted with healthy and chronic physically ill children aged 10-12 (primary school, 4th-6th grade) and 13-15 (junior high school, 1st-3rd grade) to develop an instrument to measure children's health locus of control. An eight week study provided evidence that the MHLC has acceptable levels of reliability, (test-retest reliability, r = .74), internal consistency, (coefficient alpha ranging from .73 to .78) and construct validity. Item analysis and factor analysis were performed to determine item effectiveness and existence of significant subscales. The main results concerning validity were as follows: Health behavior of healthy children was positively correlated with internal factors. Self-report with self-care behavior of children with bronchial asthma was positively correlated with internal factors. The results were discussed in reference to previous studies.

Roles of gamma-carboxylation and a sex hormone-binding globulin-like domain in receptor-binding and in biological activities of Gas6

Gas6 is a ligand for an Axl/Sky receptor tyrosine kinase subfamily and has a structure composed of a Gla domain, four EGF-like domains and a C-terminal sex hormone-binding globulin (SHBG)-like domain. When examining the role of each domain in receptor-binding and biological activities of Gas6, we found that receptor-binding and mitogenic activities were markedly reduced by inhibiting gamma-carboxylation of the Gla domain, while a Gas6 mutant composed of only an SHBG-like domain retained both of these activities. Thus, the SHBG-like domain is apparently an entity indispensable for Gas6 activities, and gamma-carboxylation of the Gla domain has a regulatory role in retaining the activity of native Gas6.

Plasmodium falciparum: allelic variation in the merozoite surface protein 1 gene in wild isolates from southern Vietnam

Allelic variation in the Plasmodium falciparum merozoite surface protein 1 (MSP1) gene is expressed as an association of allelic types in variable blocks. In this study, a PCR strategy that can detect 24 different MSP1 association types was used to investigate allelic variation in the MSP1 gene. We identified 236 distinct association type clones in 136 wild isolates collected from southern Vietnam, analysis of which revealed that (1) recombination between two representative allelic types in the central part of the MSP1 gene did not exist, (2) frequency distribution of MSP1 association types did not differ in different population groups, and (3) particular MSP1 association types were predominant. Statistical analysis for the association of allelic types indicated significant, nonrandom associations between blocks 4 and 6 but not between blocks 2 and 4, and 2 and 6. These results suggest that selection operates in favor of particular MSP1 association types. In addition, direct sequencing of 31 isolates confirmed reported sequence substitutions in the C-terminal 19-kDa Cys-rich region of MSP1, supporting a notion of limited variations in this region, a strong vaccine candidate molecule.