120 SUCCESSFUL PRODUCTION OF PIGLETS DERIVED FROM VITRIFIED MORULAE AND EARLY BLASTOCYSTS WITHOUT DIRECT EXPOSURE TO LIQUID NITROGEN

Recently piglets have been produced from morulae and early blastocysts vitrified by using methods such as open pulled straw and microdroplet. However, a problem of pollution, such as contamination of embryos with pathological microorganisms from the liquid nitrogen (LN), to the embryos is possible, because embryos must be exposed directly to LN in these methods. Therefore, we designed a new device in which the embryo is vitrified on the stainless steel chip inserted into a 0.25-mL straw without direct contact with LN. To serve as a stainless steel chip, a part of the body of a 19 G needle was cut to reveal its inner surface as the loading site for embryos, and 2 to 15 embryos in a small amount of a vitrification solution were placed on the inner surface of the needle. Then the needle with the embryos was inserted into the 0.25-mL straw which was pre-cooled in LN. This study was conducted to determine the efficiency of vitrification using the new device for porcine embryos at early developmental stages. In Experiment 1, embryos at the compact morula to early blastocyst stages were collected from 7 gilts. The embryos were equilibrated in 20 mM HEPES-buffered PZM (Yoshioka et al. 2003 Biol. Reprod. 69, 2092–2099) (H-PZM) supplemented with 1.8 M ethylene glycol (EG), and then in 1.8 M EG, 0.3 M sucrose, and 2% (w/v) bovine serum albumin (BSA) for 5 min. After equilibration, the embryos were vitrified using H-PZM supplemented with 0.6 M sucrose, 2% (w/v) BSA, and 4 M, 5 M, 6 M, or 7 M EG (ESB). The vitrified embryos were thawed, diluted by directly plunging the needle of the device into H-PZM supplemented with 1.8 M EG and 0.6 M sucrose for 5 min at 38�C, and subsequently cultured in PZM supplemented with 10% fetal bovine serum for 48 h; fresh embryos were cultured as a control group. In Experiment 2, embryos were vitrified using 5 M EG ESB, and then 56 vitrified embryos (collected from 4 gilts) were transferred to 4 recipient gilts (12 to 15 embryos per recipient). In Experiment 1, the survival rates of vitrified embryos after 48 h of culture in 4 M, 5 M, 6 M, 7 M, and control groups were 72.7, 86.4, 90.0, 87.0, and 100% (n = 20 to 23), respectively. The 4 M group showed a significantly lower survival rate than the control group (P < 0.05; chi-square test). The expanding and hatching rates of the vitrified embryos in these groups after 48 h of culture were 68.2, 77.3, 70.0, 65.2, and 95.0%, respectively. The 7 M group had a significantly lower expanding and hatching rate than the control group (P < 0.05). In Experiment 2, 3 recipients showed estrus at 19, 29, and 44 days after their previous estrus. One recipient became pregnant and 6 normal live piglets were born. These results indicated that porcine embryos at the compact morula to early blastocyst stages can survive after vitrification using our new device, which can prevent embryos from direct exposure to LN, and that piglets can be obtained from vitrified embryos without fear of pollution from LN.

Analysis of cartilage oligomeric matrix protein (COMP) degradation and synthesis in equine joint disease

REASONS FOR PERFORMING STUDY

Cartilage oligomeric matrix protein (COMP) is abundant within cartilage; its turnover and/or degradation have been investigated in various equine joint diseases and it has been suggested that COMP fragmentation might be useful for monitoring such conditions.

OBJECTIVES

To determine whether COMP metabolism is compromised in equine osteoarthritis (OA) and whether COMP degradation is a useful joint marker representing cartilage destruction.

HYPOTHESIS

A monoclonal antibody (mAb) with a higher affinity for degraded COMP allows discrimination of diseased joints by quantifying COMP levels and fragmentation.

METHODS

A mAb (clone14G4) was generated against equine cartilage COMP. The NH2-terminal sequence of enzyme-cut COMP fragments recognised by 14G4 was determined, as was the efficiency of binding to COMP (using a generated COMP peptide). COMP concentration and fragmentation were analysed in synovial fluid (SF) from normal horses and those with OA.

RESULTS

The mAb 14G4 had a higher affinity for the smaller fragments of equine COMP, compared with a mAb (clone 12C4) generated against human COMP. The 14G4 epitope was identified as between C134 and F147. The COMP values in OA (mean +/- s.d. 205.8 +/- 90.9 microg/ml) were significantly higher than in the normal (133.1 +/- 31.5 microg/ml) SF. On the immunoblots of OA sample, the proportions of intact COMP were significantly lower, while smaller fragments ranging from 75 to 290 kDa were higher compared with the normal SF.

CONCLUSIONS AND POTENTIAL RELEVANCE

The mAb 14G4 reliably detects COMP degradation as well as synthesis, and fragmentation analysis combined with quantification in SF could be useful to study equine OA.

Serum level of cartilage oligomeric matrix protein (COMP) in equine osteoarthritis

This study was designed to assay and compare cartilage oligomeric matrix protein (COMP) in horse sera, in samples from normal and joint diseased horses, and to investigate the relationships between COMP in sera and synovial fluids (SF) with keratan sulphate (KS) data. Sera from 38 horses free of any joint pathology (controls) and from horses with aseptic joint disease (AJD horses, n = 40) were assayed for COMP and KS concentrations. Of the 78 horses in the study, 53 were also assayed for COMP and KS concentrations in SF. COMP and KS were measured by inhibition ELISA, using monoclonal antibodies 12C4 and 5D4, respectively. The COMP concentration in sera from AJD horses (mean +/- s.d. 10.7 +/- 7.4 microg/ml) was significantly (P<0.02) lower than in control sera (14.8 +/- 7.8 microg/ml). The joint disease sera also had significantly lower (P<0.01) KS levels (180.5 +/- 61.8 ng/ml) than controls (237.1 +/- 116.1 ng/ml). A significant correlation (r = 0.52, n = 53, P<0.001) was seen between serum and SF in COMP levels; no such relationship was seen in KS levels. It is possible that serum COMP concentration could be a more specific marker of equine joint disease than any other described to date.

Increased plasminogen activator inhibitor activity and diabetes predict subsequent coronary events in patients with angina pectoris

BACKGROUND

Plasminogen activator inhibitor (PAI) is a marker of recurrence of myocardial infarction. Diabetes mellitus is also an important risk factor of coronary artery disease, including myocardial infarction and angina pectoris.

AIM

We examined baseline plasma PAI activity levels, clinical variables, and angiographic findings and assessed them as prospective values for subsequent coronary events, such as sudden death, nonfatal myocardial infarction and coronary revascularization by percutaneous transluminal coronary angioplasty or coronary artery bypass surgery during the follow-up period.

METHODS

We conducted a prospective study for 4 years of 249 consecutive patients admitted with angina pectoris. Blood samples for PAI were drawn at discharge.

RESULTS

In the multivariate Cox proportional hazard model, PAI activity and diabetes mellitus were significant and independent risk factors (the risk increased by 10% in those with a higher PAI concentration and by 70% in diabetic patients). Event-free survival was reduced by higher PAI activity (> or = 8.4 IU/mL) and the presence of diabetes. The patients with higher PAI activity and diabetes had a 4.2-fold risk in comparison with the patients with lower PAI activity and no diabetes. However, patients with lower PAI activity were less likely to have coronary events even when they had diabetes.

CONCLUSIONS

Higher PAI activity and diabetes predict subsequent coronary events in patients with angina pectoris. Diabetes has less prognostic value for subsequent coronary events in patients with lower PAI activity.

Measurement of cartilage oligomeric matrix protein (COMP) in normal and diseased equine synovial fluids

OBJECTIVE

This study was designed to assay cartilage oligomeric matrix protein (COMP) in equine synovial fluids and to compare the concentration in synovial fluids from normal horses with joint diseased horses. The relationship between the COMP degradation and the matrix metalloproteinase activity in synovial fluids was also investigated.

DESIGN

Using COMP antigen prepared from equine articular cartilage and murine monoclonal antibody (12C4) raised against human COMP, an inhibition ELISA was developed. COMP in equine synovial fluids from normal and diseased joints was quantified. Metalloproteinase activities were evaluated in the same synovial fluids by a gelatin degradation ELISA. COMP fragments were evaluated qualitatively by Western blotting.

RESULTS

The COMP inhibition ELISA was reliable at concentrations of equine COMP between 62.5 and 2000 ng/ml. COMP values in joint fluids in both aseptic and septic joint disease (19.7+/-15.3 and 16.1+/-11.2 microg/ml, respectively) were significantly (P < 0.001) lower than normal (53.2+/-29.0 microg/ml). The molecular sizes of COMP on immunoblots were different between normal and diseased synovial fluids; more fragments were seen in diseased fluids. The aseptic (26.6 +/- 20.6%) and septic joint disease synovial fluids (36.1 +/- 37.5%) had significantly higher (P < 0.02 and 0.002, respectively) gelatinolytic activities than normal (13.6 +/- 13.7%). There was a negative correlation (R = -0.31, P < 0.002) between COMP level and gelatinase activity. Conclusions We conclude that the fragment pattern and the absolute COMP concentration maybe useful for monitoring joint disease, and that COMP degradation in synovial fluids from progressed joint disease may be due to MMP gelatinolytic activity.

Evaluation of collagenase-induced mitral valve regurgitation in dogs

OBJECTIVE

To investigate the hemodynamic changes induced by injecting collagenase into the mitral valve to induce mitral valve regurgitation (MVR) in dogs.

ANIMALS

9 healthy Beagles.

PROCEDURE

Dogs were randomly assigned to 3 groups: control (saline [0.9% NaCl] solution; n = 3), single collagenase injection (C1; 3), and 2 collagenase injections (C2; 3). Open-heart surgery was performed, and saline or collagenase solutions were injected into the mitral valve. Before and weekly for 11 weeks after surgery, radiography, echocardiography, and phonocardiography were performed. Mean pulmonary arterial pressure and mean pulmonary arterial wedge pressure (mPAWP) were measured before and 11 weeks after surgery. Postmortem examinations were performed after dogs were euthanatized.

RESULTS

No changes were detected in the control group during the 11-week follow-up period. A systolic murmur and MVR developed 1 week after surgery in groups C1 and C2. The murmur changed from a protosystolic to a pansystolic murmur, and left atrial diameter and the left atrial-to-aortic root diameter ratio increased with time. Mean pulmonary arterial pressure and mPAWP were greater 11 weeks after surgery in groups C1 and C2, compared with presurgery values. During necropsy, tissue loss was detected in the mitral valve at the site of collagenase injection. Degree of regurgitation corresponded to lesion size.

CONCLUSIONS AND CLINICAL RELEVANCE

Injection of collagenase into the mitral valve of healthy dogs induced MVR, and dogs with MVR developed progressive hemodynamic changes without acute overload. Collagenase-induced MVR may be an appropriate model for evaluation of prognostic markers of idiopathic MVR in dogs.

Uterine horn torsion in two non-gravid bitches

Uterine torsion secondary to sacculation of the uterine horns was diagnosed in two non-gravid bitches which were presented with anorexia, polydipsia and an acutely swollen abdomen. On the basis of the radiological and ultrasonographic findings, which indicated the presence of an enlarged spherical or tubular structure filled with hypoechoic material in the caudal abdomen, a tentative diagnosis of pyometra was made. Exploratory laparotomy revealed unilateral uterine horn torsion along the longitudinal axis, with bilateral fluid-filled sacculations. Ovariohysterectomy was performed in both cases. Pathological examination of the uteri demonstrated haematometra in one dog and pyometra in the other.

Increased blood vascular endothelial growth factor levels in patients with acute myocardial infarction

Vascular endothelial growth factor (VEGF) is a growth factor for vascular endothelial cells in vitro. The present study was designed to determine whether serum VEGF levels increase in patients with acute myocardial infarction (AMI) compared with patients with stable exertional angina and control subjects, and to examine the serial changes of serum VEGF levels in patients with AMI. We examined serum VEGF levels by using antibody prepared from serum immunized with human VEGF(121). The serum VEGF level (pg/ml) was higher (p < 0. 0001) on admission in the patients with AMI (177 +/- 19) than in those with stable exertional angina (61 +/- 7) and control subjects (62 +/- 6). The serum VEGF level (pg/ml) of the patients with AMI was 177 +/- 19 on admission, 125 +/- 9 on day 3, 137 +/- 11 on day 5, 242 +/- 18 at 1 week, and 258 +/- 22 at 2 weeks after admission. The value was higher on admission than on day 3 after admission (p = 0.014), the values were higher at 1 week and 2 weeks than on admission, on day 3, and 5 (p < 0.01). Furthermore, there were correlations between peak VEGF levels at 1 week or 2 weeks after admission and peak creatine kinase levels. The increase of VEGF on admission in the patients with AMI may be due to the hypoxia of acute myocardial ischemia. The elevation at 1 week and 2 weeks from the onset may cause the development of collateral circulation in relation to the healing of the infarction site.

The effect of heparin on tissue factor and tissue factor pathway inhibitor in patients with acute myocardial infarction

We examined plasma TF and free TFPI levels in 26 consecutive patients with AMI, 26 patients with stable exertional angina, and 25 patients with chest pain syndrome. In patients with AMI, blood samples were obtained immediately after admission and at 4, 8, 16, 24, and 48 h, and the third, fifth, seventh, and fourteenth day after initiation of reperfusion therapy. Plasma TF levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups (248.0+/-117. 4 vs. 179.5+/-29.2 vs. 189.5+/-29.6 pg/ml, P<0.01). In patients with AMI, the level subsequently decreased after heparin administration and was maintained at significantly lower levels compared to those on admission. Plasma free TFPI levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups [33.5+/-12.4 vs. 26.0+/-7.6 ng/ml (P<0.01) vs. 27.5+/-6.3 ng/ml, P<0.05]. In patients with AMI, it reached the maximum level at 4 h after the administration of heparin, and gradually decreased over the time course. These data indicated that continuous administration of a low dose of heparin was effective in decreasing TF levels without affecting TFPI levels. Our results elucidate one of the mechanisms by which the administration of heparin is beneficial in AMI patients undergoing percutaneous revascularization.

Usefulness of three-dimensional visualization of coronary arteries using electron-beam computed tomography data with volume rendering

Three-dimensional images of the coronary arteries using electron-beam computed tomography (EBCT) data with shaded surface rendering makes it possible to achieve images easily with a short reconstruction time. However, a lower threshold is required to estimate vessel diameters and there is a quantitative problem compared with conventional coronary arteriography. In combination with volume rendering, EBCT may be useful to detect the normal coronary artery wall, the major components of the atherosclerotic plaque (lipid, fibrous connective tissue and calcium). EBCT scans offer a new, non-invasive alternative to conventional coronary arteriography for diagnosis of coronary artery disease.

Increased plasma level of soluble E-selectin in acute myocardial infarction

BACKGROUND

E-selectin, also known as endothelial cell leukocyte adhesion molecule-1, is a member of the selectin family of adhesion molecules and is expressed on vascular endothelial cells in inflammatory reactions. The induction of surface E-selectin expression by endothelial cells is considered a marker of activation.

METHODS AND RESULTS

We examined the plasma soluble E-selectin (sE-selectin) level in 41 patients within 6 hours after the onset of acute myocardial infarction (AMI) and in 37 patients with stable exertional angina and 27 control patients. Blood samples were obtained on admission, after reperfusion therapy, and at 4 hours, 8 hours, 12 hours, 24 hours, 48 hours, 3 days, 5 days, 1 week, and 2 weeks after admission in the AMI group. In this group, 21 patients had a history of prodromal unstable angina before infarction and 20 had sudden onset of infarction. The plasma sE-selectin level (ng/mL) on admission was higher in the AMI group than in the stable exertional angina group and control group (38.5 +/- 3.1 vs 28.5 +/- 1.5, P <.01, 26.0 +/- 1.8, P <.01, respectively). In addition, plasma sE-selectin levels were higher in the patients with AMI with prodromal unstable angina than in those with a sudden onset of infarction on admission (44.7 +/- 5.4 vs 32.0 +/- 2.1, P <.05). The plasma sE-selectin level decreased slowly during the chronic phase both in patients with AMI with prodromal unstable angina (from 44.7 +/- 5.4 to 33.8 +/- 3.4, P <.01) and those with a sudden onset of infarction (from 32.0 +/- 2.1 to 24.9 +/- 2.4, P <.01).

CONCLUSIONS

These results suggest that an increase of sE-selectin may reflect enhanced endothelial cell activation in patients with AMI. The higher sE-selectin level in patients with AMI with prodromal unstable angina may have been associated with repeated episodes of myocardial ischemia and reperfusion.

[Right thoracotomy for reoperative mitral valve replacement]

We report a case of 67-year-old male who underwent reoperative mitral valve replacement through the right thoracotomy. He had undergone primary double valve replacement with mechanical valve for aortic valve and tissue valve for mitral valve respectively, and tricuspid annular plasty 11 years ago. The second operation was performed through the right thoracotomy under moderately hypothermic cardiopulmonary bypass. The mechanical valve was replaced via right side of left atrium approach under ventricular fibrilation at 25 centigrade of bladder temperature. He recovered well without any major complications.

Hemodynamic effects of intravenous administration of olprinone hydrochloride on experimental pulmonary hypertension

To examine acute effects of olprinone hydrochloride (CAS 106730-54-0, Coretec) on pulmonary hypertension, hypoxic pulmonary hypertension was produced in 6 adult Beagle dogs. Using this pulmonary hypertension model, single intravenous bolus injections of olprinone at doses of 10, 30 and 100 micrograms/kg were administered at 5-min intervals and hemodynamic parameters were evaluated. Heart rate increased at doses of 30 and 100 micrograms/kg, but did not change at a dose of 10 micrograms/kg. Mean aortic pressure, mean pulmonary arterial pressure, pulmonary vascular resistance and systemic vascular resistance and right ventricular stroke work index did not change at doses of 10 and 30 micrograms/kg, but they decreased significantly at a dose of 100 micrograms/kg. On the other hand, cardiac index and the first derivative value of the left ventricular pressure did not show significant change at all doses. These results indicate the vasodilating effects on peripheral and pulmonary vessels in hypoxic model at high doses of olprinone. Its application in right heart failure accompanied by pulmonary hypertension therefore is expected to yield promising results.

The risk of contrast media-induced ventricular fibrillation is low in canine coronary arteriography with ioxilan

Previous studies have proposed that sodium supplement to nonionic contrast media (CM) can decrease the risk of ventricular fibrillation (VF). This study was designed to compare the occurence of VF induced by ioxilan (containing 9 mmol/LNa+) with other nonionic CMs. After wedging a catheter in the right coronary artery, test solutions including ioxilan, ioversol, iomeprol, and iopromide were infused for 30 sec at the rate of 0.4 ml/sec or until VF occurred. Then, incidence of VF, contact time (i.e. the time required to produce VF), and QTc were measured. Also, the CMs other than ioxilan were investigated at sodium levels adjusted to 9 and 20 mmol/L Na+. The incidence of VF with ioxilan (0%) was the lowest of all. In the other CMs, the incidence decreased in accordance with increase of sodium. Iomeprol and iopromide showed significant reduction of VF incidence at the sodium level of 20 mmol/L. The higher sodium supplements also prolonged the contact times. The increase of QTc was the greatest in ioxilan. Ioxilan has the least arrythmogenic property among the current low-osmolality nonionic CMs. This property might be attributable to an optimal sodium concentration of 9 mmol/L in the CM.

Salt water promotes hypertension in Dahl-S rats

Hypertension was induced in Dahl-salt-sensitive (Dahl-S) rats by administering salt in drinking water. Control rats receiving tap water did not show a significant change in blood pressure or abnormalities in the kidney. Rats receiving 0.5% NaCl solution developed moderate hypertension and renal lesions. Rats receiving 1.0% NaCl solution showed prominent and increasing hypertension and severe renal damage. This method of salt administration should be simpler than administration in the diet as a means of promoting renal hypertension. The lower concentration salt water caused chronic mild hypertension in Dahl-S rats, and may serve as a useful model for progressive hypertension.

Angiotensin-converting enzyme inhibition reduces monocyte chemoattractant protein-1 and tissue factor levels in patients with myocardial infarction

OBJECTIVES

We investigated the effects of enalapril therapy on plasma tissue factor (TF), tissue factor pathway inhibitor (TFPI) and monocyte chemoattractant protein-1 (MCP-1) levels in patients with acute myocardial infarction.

BACKGROUND

Macrophages express TF in human coronary atherosclerotic plaques. Both TF and TFPI are major regulators of coagulation and thrombosis. Monocyte chemoattractant protein-1 is a monocyte and macrophage chemotactic and activating factor.

METHODS

In a randomized, double-blind, placebo-controlled study beginning about two weeks after myocardial infarction, 16 patients received four weeks of placebo (placebo group) and another 16 patients received four weeks of enalapril 5 mg daily therapy (enalapril group). We performed blood sampling after administration of the doses.

RESULTS

There were no significant differences in the serum angiotensin-converting enzyme (ACE) activity, plasma TF, free TFPI or MCP-1 levels before administration between the enalapril and placebo groups. In the enalapril group, ACE activity (IU/liter) (14.0 before, 5.2 on day 3, 5.8 on day 7, 6.3 on day 28), TF levels (pg/ml) (223, 203, 182, 178) and MCP-1 levels (pg/ml) (919, 789, 790, 803) significantly decreased by day 28. However, the free TFPI levels (ng/ml) (28.2, 26.5, 26.8, 28.4) did not change. These four variables were unchanged during the study period in the placebo group.

CONCLUSIONS

This study demonstrated that administration of enalapril reduces the increased procoagulant activity in patients with myocardial infarction associated with inhibition of the activation and accumulation of macrophages and monocytes.

Association of plasma levels of activated protein C with recanalization of the infarct-related coronary artery after thrombolytic therapy in acute myocardial infarction

Protein C is one of the most important antithrombotic components. After activation by the thrombin-thrombomodulin complex on endothelial cells, activated protein C (APC) inactivates factors Va and VIIIa, which leads to the inhibition of thrombin formation. We examined the association of plasma levels of APC with the responsiveness to coronary thrombolytic therapy of the infarct-related coronary artery in patients with acute myocardial infarction (AMI). Plasma levels of APC, thrombin-antithrombin III complex (TAT), and plasminogen activator inhibitor (PAI) activity were measured in 32 consecutive AMI patients who underwent coronary angiography followed by thrombolytic therapy, and compared to the measurements in 23 control subjects. On admission, APC levels (ng/mL) were significantly elevated in patients with AMI, as compared with controls (2.5+/-0.4 vs. 1.2+/-0.2, 1.3+/-0.2, respectively, p<0.01). At discharge, plasma levels in AMI patients decline to values not significantly different from those in controls. (1.2+/-0.2, 1.3+/-0.2, respectively). TAT levels (ng/mL) were different among the groups in a fashion similar to that of APC (14.1+/-3.1 on admission vs. 3.3+/-0.4 at discharge, 1.8+/-0.1 in the control subjects, respectively, p<0.01). PAI activity levels (IU/mL) were higher on admission than at discharge and higher than the control subjects (19.7+/-1.8 vs. 10.5+/-1.0, 5.4 +/- 0.7, respectively, p<0.01). Thirty-two patients with AMI were classified into two groups according to the results of thrombolysis: the success group (24 patients) and the failure group (eight patients). APC levels were higher in the failure group than in the success group (5.1+/-0.7 vs. 1.6+/-0.2, p<0.01). TAT levels were also higher in the failure group than in the success group (30.8+/-9.6 vs. 8.6+/-1.7, p<0.01). PAI activity levels (IU/mL) were lower in the failure group than in the success group (13.5+/-3.1 vs. 21.7+/-2.1, p<0.05). There were correlations between APC and TAT levels both on admission (r=0.75, p<0.0001) and at discharge (r=0.71, p<0.0001). Elevated APC was thought to correlate with increased thrombin generation in patients with AMI. This study demonstrated that there was a significant relation between plasma APC level and the responsiveness to thrombolytic therapy of the infarct artery. This study may also indicate that increased thrombin generation is a cause of the resistance to thrombolytic therapy.

Heightened tissue factor associated with tissue factor pathway inhibitor and prognosis in patients with unstable angina

BACKGROUND

This study was designed to evaluate the plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with unstable angina and investigate whether there is a relationship between these levels and unfavorable outcome.

METHODS AND RESULTS

The plasma TF and free TFPI antigen levels were determined in plasma samples taken from 51 patients with unstable angina, 56 with stable exertional angina, and 55 with chest pain syndrome. The plasma TF and free TFPI antigen levels were higher in the unstable angina group than in the stable exertional angina and chest pain syndrome group. There was a good correlation between TF and TFPI. We established borderline as maximum level in the patients with chest pain syndrome. Seven patients (of the 22 in the high TF group) required revascularization to control their unstable angina during in-hospital stay. On the other hand, only 1 of the 29 patients in the low TF group required myocardial revascularization. Four patients of the 14 patients in the high free TFPI group required myocardial revascularization during in-hospital stay, and 4 of the 37 patients in the low free TFPI group required myocardial revascularization. We compared the TF and free TFPI levels between the cardiac event (+) group and cardiac event (-) group. TF levels were significantly higher in the cardiac event (+) group than in the cardiac event (-) group.

CONCLUSIONS

We have demonstrated that not only the plasma TF levels but also the plasma-free TFPI levels are elevated in patients with unstable angina. Patients with unstable angina and heightened TF and free TFPI are at increased risk for unfavorable outcomes. The heightened TF level was a more important predictor in patients with unstable angina.

Regional blood flow distribution from the proximal arterial cannula during veno-arterial extracorporeal membrane oxygenation in neonatal dog

Extracorporeal membrane oxygenation (ECMO) is frequently used for treatment of patients with severe hypoxemia due to life-threatening respiratory failure. Due to this hypoxemia, the myocardium of these patients is insufficiently provided with oxygen, and consequently their cardiac function commonly deteriorates. But veno-arterial (V-A) ECMO provides oxygenated blood to the coronary arteries from ECMO circuit insufficiently. To increase the coronary blood flow distributed from ECMO, we placed the arterial cannula 1 cm above the aortic valve and evaluated the regional blood from the proximal arterial cannula in comparison with the distal cannula. Eight neonatal dogs weighting 1.8-2.5 kg were supported by V-A ECMO. The regional blood flow from the arterial cannula was measured by injection of colored microspheres into ECMO circuit. The site of the arterial cannula was changed under fluoroscopy. The bypass flow was maintained at either 50 or 100 ml/min/kg. We found that the coronary blood flow distributed from the proximal arterial cannula was significantly higher than that from the distal cannula. The proximal arterial cannula appears necessary to provide sufficient oxygenated blood to the coronary circulation during V-A ECMO. Therefore, it is expected that the increased cardiac function may improved, and that the survival rate of the patients with retarded cardiac function due to severe hypoxemia may increase by proximal placement of the arterial cannula during V-A ECMO.

Experimental His-bundle pacing: histopathological and electrophysiological examination

His-bundle pacing gives a more physiological ventricular contraction in comparison to right ventricular apical pacing. However the problems of lead fixation and stability of long-term His-bundle pacing are yet unsolved. We used six adult beagles, in which a screw-in lead was anchored in the His-bundle region for observation of the pacing conditions and histopathologic changes of the conduction system over the course of 2 months. In the results, a satisfactory fixation was obtained using a conventional screw-in lead and no histological influence on the conduction system was observed. The pacing threshold at the time of implantation was 1.15 +/- 0.69 V (3.23 +/- 3.08 mA) in the pulse width of 0.5 ms. R wave amplitude, the impedance and slew rate were 7.28 +/- 2.04 mV, 409 +/- 102 Ohm, and 0.65 +/- 0.41 V/s, respectively. Two months later, these parameters changed to 2.83 +/- 1.06 V (10.4 +/- 5.71 mA), 5.63 +/- 1.62 mV, 310 +/- 71.3 Ohm, and 0.49 +/- 0.22 V/s, respectively. These results suggest the feasibility of clinical application of permanent His-bundle pacing.

Relationship between serum angiotensin-converting enzyme activity and plasma plasminogen activator inhibitor activity in patients with recent myocardial infarction

BACKGROUND

An elevated level of angiotensin-converting enzyme (ACE) has been demonstrated to increase the risk of myocardial infarction. Plasminogen activator inhibitor (PAI) is the most important physiological inhibitor of tissue plasminogen activator in plasma. An elevated level of PAI has been reported to be associated with decreased fibrinolytic capacity and to constitute a marker of the risk for recurrent coronary thrombosis.

METHODS

We measured the serum ACE activity and plasma PAI activity in 34 patients with recent myocardial infarction, and evaluated the correlation between these two values by linear regression analysis. We also administered captopril (37.5 mg/day) to 17 of these patients and placebo to the other 17 patients at random, and compared the changes in PAI activity and ACE activity in these two groups over a 1-month period.

RESULTS

There was a significant correlation between the serum ACE activity and the plasma PAI activity at baseline in the patients (r = 0.498, P < 0.01). The captopril-treated patients showed significantly reduced PAI activity (P < 0.01), and a concomitant decrease in ACE activity.

CONCLUSION

These results suggest that elevated ACE activity is associated with impaired fibrinolysis and that treatment with an ACE inhibitor improves the fibrinolytic function in patients with recent myocardial infarction. The results also suggest that the renin-angiotensin system plays a role in the increased risk of ischemic cardiovascular events when it is activated, and in the reduction of risk of recurrent myocardial infarction by ACE inhibition.

Development of atherosclerotic lesions in cholesterol-loaded rabbits

To examine both of the target vessels and the optimal time of their endothelial denudation to study vascular restenosis after balloon injury in cholesterol-loaded rabbits, we made 36 atherosclerotic rabbits by feeding a hypercholesterol diet, and histologically examined the onset time and the development of atherosclerosis. Atheromatous changes were observed first after the 5th week in the thoracic aorta from the start of the diet, and then extended to the abdominal aorta, coronary artery with time. The atherosclerotic lesions in the thoracic aorta and the proximal portion of the coronary artery showed high-grade concentric intimal thickening with luminal stenosis. The abdominal aortic lesion mildly progressed. In the renal, carotid and femoral arteries, in contrast, slight atheroscleromatous changes developed during the diet period. These results suggest that the thoracic and abdominal aortas and the coronary artery would be suitable as target vessels to study vascular restenosis after balloon injury, and the endothelial denudation of these vessels should be performed between the 8th and 15th week in this diet protocol for an accurate analysis.

Plasma soluble intercellular adhesion molecule-1 levels in coronary circulation in patients with unstable angina

It has been suggested that active inflammation plays an important role in the pathogenesis of acute coronary syndromes, including unstable angina. Intracellular adhesion molecule-1 (ICAM-1) is a major ligand on the endothelial cells for adherence of the activated polymorphonuclear leukocytes. Recently, it has been demonstrated that the soluble form of ICAM-1 has been detected in human serum and has been increased in many other inflammatory or autoimmune disorders. To evaluate the involvement of ICAM-1 in unstable angina, we examined plasma soluble ICAM-1 (sICAM-1) levels in coronary circulation. The plasma sICAM-1 levels in the coronary sinus and aortic root were simultaneously examined in 20 patients with unstable angina, 19 patients with stable exertional angina, and 16 control subjects. The plasma levels of sICAM-1 were measured by enzyme-linked immunosorbent assay. The mean plasma sICAM-1 levels (nanograms per milliliter) both in the coronary sinus and aortic root were significantly higher (p <0.01) in patients with unstable angina than in those with stable exertional angina and in control subjects (217+/-14 vs 126+/-8; 120+/-10 in the coronary sinus, 202+/-13 vs 125+/-9; 123+/-10 in the aortic root). Furthermore, the mean value was higher in the coronary sinus than in the aortic root in patients with unstable angina. There were no significant differences in the values between in the coronary sinus and aortic root in patients with stable exertional angina and control subjects. Thus, sICAM-1 release is increased, especially in coronary circulation in unstable angina.

Plasma tissue factor pathway inhibitor and tissue factor antigen levels after administration of heparin in patients with angina pectoris

The hypercoagulability is associated with expression of tissue factor in patients with angina. Tissue factor pathway inhibitor regulates the extrinsic coagulation pathway mediated by tissue factor. Plasma samples were obtained from 14 patients with angina pectoris and 9 with chest pain syndrome before and 5, 30, 60, and 120 minutes after administration of heparin (50 IU/kg). The tissue factor and prothrombin fragment 1+2 levels before administration were elevated in patients with angina pectoris and were reduced to the levels of chest pain syndrome after the administration. The free tissue factor pathway inhibitor levels after the administration were higher in patients with angina pectoris than in patients with chest pain syndrome. Plasma tissue factor pathway inhibitor levels correlated positively with plasma tissue factor and prothrombin fragment 1+2 levels. We showed that plasma-free TFPI levels after administration of heparin, which may indicate endothelial cell associated TFPI levels, increased in patients with angina pectoris compared with patients with chest pain syndrome. Increased endothelial cell associated TFPI was associated with hypercoagulability in patients with angina pectoris. These may help to explain the reduction in thrombotic risk associated with the use of heparin.

Circulatory arrest under hypothermic anesthesia using abdominal cavity cooling

The purpose of this study was to investigate the potential for circulatory arrest during surgery under systemic hypothermic anesthesia, using the abdominal cavity cooling method. Eighteen beagles, each weighing 10.5 +/- 2.3 kg, were cooled by filling the abdominal cavity with crushed ice. Just after the esophageal temperature reached 30 degrees C, the heart was exposed, and a left-heart bypass from the left atrium to the aortic root was created. At 20-23 degrees C, the heart was arrested by infusing cooled Young's solution into the aortic root. After a period of cardiac arrest, resuscitation and rewarming were initiated simultaneously. Throughout these procedures, an electrocardiogram (ECG) and the arterial blood pressure (ABP) were monitored continuously. Hematocrit (Ht), total protein (TP), and arterial blood pH and gases were measured every 30 min. The recoveries after surgery were divided into three types as follows, 1) recovery without any complications-11 dogs, 2) not extubated with spontaneous breathing-4 dogs, 3) no reappearance of heart beat-3 dogs. PaO2 during resuscitation was significantly higher in dogs which recovered completely than in the rest of the dogs. These results suggest that hypothermia induced by the abdominal cavity cooling method could be useful for organ-protection during open-heart surgery, and that successful recovery may be attained through protection of the lung as well as the myocardium.