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Biomedical subjects

T Kawagoe

Publications and source records attributed to T Kawagoe.

At least 37 records · Page 2Linked to original sources
PubMed1997

Directional coronary atherectomy for the treatment of acute myocardial infarction.

Directional coronary atherectomy (DCA) was performed after intracoronary thrombolysis in 32 patients with a first acute myocardial infarction. DCA was successful in 31 (97%) of 32 patients. Abrupt closure of the treated segment occurred in one patient but was managed successfully by conventional balloon angioplasty. Repeat angiography was performed in 32 patients before discharge (2.7 +/- 0.7 weeks later) and in 29 patients during the follow-up (4.5 +/- 1.5 months later). No restenosis (stenosis > 50%) occurred before discharge; however restenosis occurred in 12 (41%) of 29 patients during follow-up. The restenosis rate in patients with subintimal resection was significantly higher than in those with intimal resection (78% vs 25%, p < 0.01). These data suggest that DCA in patients with acute myocardial infarction is feasible for persistent early patency of the infarct-related coronary artery, but late restenosis continues to limit success and subintimal resection may increase the restenosis rate during the follow-up.

Aged↗
PubMed1997

Clinical implications of cigarette smoking in acute myocardial infarction: acute angiographic findings and long-term prognosis.

This study was undertaken to assess whether reperfusion in smokers could be achieved spontaneously or therapeutically and to assess whether favorable outcome in smokers could be sustained for years after infarction. We studied 260 patients with anterior myocardial infarction who underwent coronary angiography and thrombolysis within 24 hours after the onset of chest pain. There were 158 smokers and 102 nonsmokers. Smoking was associated more with men, younger age, and less multivessel disease. On initial angiography, the distribution of Thrombolysis in Myocardial Infarction grade was similar between smokers and nonsmokers. After thrombolysis, Thrombolysis in Myocardial Infarction grade 3 was more frequent in smokers (32% vs 18%; p = 0.004). In-hospital mortality rates were lower (8% vs 18%; p = 0.022) and long-term cardiac survival was better in smokers (5-year survival: 82% vs 70%; p = 0.022). Our data demonstrated that the infarct artery of smokers responded more efficiently to thrombolysis and favorable outcome in smokers was sustained throughout 5 years.

Aged↗
PubMed1997

Implications of prodromal angina pectoris in anterior wall acute myocardial infarction: acute angiographic findings and long-term prognosis.

OBJECTIVES: This study was undertaken to assess how prodromal angina affects long-term prognosis after acute myocardial infarction. BACKGROUND: Although it has been reported that prodromal angina occurring shortly before the onset of acute myocardial infarction has protective effects against ischemia, its implication for long-term prognosis remains unclear. METHODS: We studied consecutive 350 patients with anterior myocardial infarction who underwent coronary angiography within 24 h after the onset of chest pain. Follow-up was achieved for 340 patients (97%). RESULTS: Eighty-nine patients had one or more episodes of angina within 24 h before infarction. On initial angiography, patients with prodromal angina in the 24 h before infarction had a patent infarct-related artery more frequently than did those without prodromal angina (34% vs. 22%, p = 0.03). Among 213 patients who underwent thrombolytic therapy for an occluded infarct-related artery, reperfusion was more frequently achieved in patients with prodromal angina in the 24 h before infarction (76% vs. 56%, p = 0.01). Prodromal angina in the 24 h before infarction was associated with a lower in-hospital mortality rate (6% vs. 14%, p = 0.02) and better 5-year survival (p = 0.009). There was no significant difference in survival between patients with previous angina at any time (n = 202) and those without. Multivariate analysis showed that prodromal angina in the 24 h before infarction was an independent factor related to 5-year survival after acute myocardial infarction (odds ratio 0.49, p = 0.04). CONCLUSIONS: Prodromal angina occurring shortly before the onset of infarction, but not previous angina itself, has a beneficial effect on long-term prognosis after infarction, suggesting a relation to ischemic preconditioning.

Aged↗
PubMed1997

Effects of volume loading on pulmonary venous flow and its relation to left atrial functions.

Although pulmonary venous (PV) flow is closely related to left atrial (LA) pressure dynamics, few investigators have discussed it in relation to LA functions, i.e., reservoir, conduit, and booster pump functions. We examined changes in PV flow rate, LA dimension, and left ventricular filling volume in 11 dogs, and assessed the effects of multistaged volume loading on PV flow and LA functions. Systolic PV flow rate (S) increased significantly and reached a plateau, reflecting a limited LA reservoir function. Diastolic PV flow rate (D) increased significantly with an increase in LA pressure. S/D ratio increased non-significantly from 0.87 +/- 0.07 before volume loading to 0.96 +/- 0.08 until S reached a plateau and then decreased to 0.76 +/- 0.08 (p < 0.05) because of a significant increase in D without an increase in S at the higher stages of volume loading. During atrial contraction, increases in LA active shortening and left ventricular filling volume were limited, indicating a limited LA forward ejection. The difference between PV flow rate just before and at the end of atrial contraction increased and correlated positively with left ventricular end-diastolic pressure (r = 0.57, p < 0.01). PV flow varies according to the degree of volume loading and reflects LA functions, which exhibit limited increases in response to volume loading.

Animals↗
PubMed1997

Effects of various doses of intracoronary verapamil on coronary resistance vessels in humans.

To investigate the vasodilatory effect of various doses of intracoronary verapamil on coronary resistance vessels, we studied 13 patients with normal angiograms. A coronary Doppler guide wire was inserted into the left anterior descending coronary artery, and coronary blood flow velocity (CBFV) was measured. Verapamil was injected into the left coronary artery at doses of 0.1 mg, 0.5 mg, 1.0 mg, and 2.0 mg at 10-min intervals. Nitroglycerin was also injected into the same artery to avoid changes in cross-sectional area. As a measure of coronary vascular resistance, coronary vascular resistance index (CVRI) was calculated as the quotient of mean aortic pressure/CBFV. An injection of verapamil produced a dose-dependent increase in CBFV: 79 +/- 38% with 0.1 mg, 131 +/- 56% with 0.5 mg, 143 +/- 46% with 1.0 mg, and 128 +/- 47% with 2.0 mg of verapamil. The percent peak decreases in CVRI were dose dependent: -42 +/- 13% with 0.1 mg, -50 +/- 17% with 0.5 mg, -62 +/- 14% with 1.0 mg, and -60 +/- 9% with 2.0 mg of verapamil. Thus, intracoronary verapamil produces a dose-dependent dilation of coronary resistance vessels, and the optimal effect is produced with an injection of verapamil at a dose of 1.0 mg into the left coronary artery. At this dose, verapamil did not affect atrioventricular conduction.

Adult↗
PubMed1997

Tonic fiber in Mauremys (Clemmys) japonica jaw muscle.

The jaw muscles of a turtle [Mauremys (Clemmys) japonica (MCJ)], have been analyzed for the histochemical characteristics of their fiber types. Six jaw muscles of the MCJ have been analyzed for histochemical characteristics of their fiber types. In this study, fiber types in two groups of muscles are classified; 1) fast twitch glycolytic (FG), fast twitch oxidative glycolytic (FOG), slow twitch oxidative (SO), and tonic fibers, according to the system of Putnam et al. (1980); 2) reacted differently in similar histochemical tests and classified, respectively, as various types. Especially tonic fibers constituted low percentage in the MAMP (ca., 0.3%), MI (ca., 3.9%) and MPtp (ca., 1.0%) were found. These results suggested that the tonic fiber plays a small part of the function in jaw movement.

Animals↗
PubMed1997

Distribution of macromolecular components in the muscle-bone junction of human masticatory muscles.

At the muscle-bone junction, the attachment is composed of macromolecular components that differ from those in masticatory muscles. In the temporal and lateral pterygoid muscles, numerous fine fibers form complex arrangements between collagenous bundles and the tendon-bone junctions. Collagenous bundles are directly inserted into the bone tissue at the site of the adhesive attachment. Reticular fibers are arranged irregularly and cover the collagenous bundles as a network. Numerous collagenous fibers are also tightly connected with the bundles that are found near the muscle-bone junction of the lateral pterygoid muscle. Strong or moderate staining for collagen types I, III, and V, tenascin, laminin, and fibronectin was observed in close association with the border of the bone matrix. Different distributions of these macromolecular components were found in each masticatory muscle. The results suggest that the morphological properties of the muscle-bone junction of each muscle reflect the tension or the stretch applied to a mandible bone. The distribution of macromolecular components in each muscle also reflects the form and calcification of the mandibular bone during aging.

Alveolar Process↗
PubMed1997

[Histological findings of specimens obtained by directional coronary atherectomy from patients with acute myocardial infarction].

The histological characteristics of acute myocardial infarction were examined in specimens obtained from infarct-related coronary artery lesions (20 left anterior descending artery, 2 left circumflex artery, 8 right coronary artery) in 30 patients with initial acute myocardial infarction who underwent directional coronary atherectomy following intracoronary thrombolysis within 6 hours after the onset of chest pain. Resected tissues were fixed in 10% buffered formalin and embedded in paraffin, and the 4 microns-thick paraffin sections were stained with hematoxylin-eosin and examined by light microscopy. Thrombus and/ or intramural hemorrhage were present in all samples. There were high incidences of cholesterol cleft in 19 (63%), foam cell in 21 (70%), calcium deposit in 19 (63%) and intimal proliferation in 16 (53%). These data suggest that thrombus and/or intramural hemorrhage are important in the onset of acute myocardial infarction.

Aged↗
PubMed1996

Time course of impaired coronary flow reserve after reperfusion in patients with acute myocardial infarction.

To evaluate the time course of coronary flow reserve after reperfusion, 14 patients with a first anterior wall acute myocardial infarction who underwent successful coronary angioplasty within 6 hours after symptom onset were studied. After angioplasty, coronary flow reserve of the left anterior descending artery was measured with a coronary Doppler guidewire and intravenous dipyridamole (0.56 mg/kg over 4 minutes). Measurements were repeated at predischarge (16 +/- 3 days, n = 12) and at follow-up (6 +/- 3 months, n = 9). Patients with restenosis at the time of repeat catheterization were excluded. An additional 13 patients with normal angiograms served as reference patients. Coronary flow reserve was 1.33 +/- 0.29 after angioplasty. It increased to 1.88 +/- 0.36 at predischarge (p <0.01) and further to 2.34 +/- 0.38 at follow-up (p <0.01 vs after angioplasty and at predischarge, respectively). However, compared with reference patients (3.15 +/- 0.48), coronary flow reserve was significantly reduced in the infarct patients even at follow-up (p <0.01). In infarct patients, the infarct region wall motion was initially -3.86 +/- 0.67 SD/chord. It significantly improved to -2.07 +/- 1.04 SD/chord at predischarge (p <0.01) and to -1.67 +/- 1.43 SD/chord at follow-up (p <0.01). However, there was no significant relation between coronary flow reserve and region wall motion after angioplasty (r = 0.10), at predischarge (r = 0.35), and at follow-up (r = 0.28). Thus, coronary flow reserve is severely impaired early after reperfusion. Coronary flow reserve improves over 2 weeks, but the impairment persists at 6 months after acute myocardial infarction. The impairment of coronary flow reserve cannot be predicted by left ventricular function. Small sample size is a potential limitation of this study, and a larger study should be performed to confirm these findings.

Aged↗
PubMed1996

Attenuation of the no-reflow phenomenon after coronary angioplasty for acute myocardial infarction with intracoronary papaverine.

The no-reflow phenomenon is observed as reduction of coronary blood flow on the angiograms (angiographic no-reflow) after immediate percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI). To assess whether a potent coronary microvascular dilator--papaverine--could attenuate the no-reflow phenomenon, nine patients with AMI who were found to have angiographic no-reflow after PTCA were studied. Angiographic no-reflow was defined as the Thrombolysis in Myocardial Infarction flow grade 1 or 2 without any mechanical obstructions in the epicardial artery. A bolus dose of 10 mg of intracoronary papaverine was administered, and the flow grade was again evaluated. Intracoronary papaverine caused a significant improvement of the flow grade (p= 0.0152). The number of cineframes that were required for the contrast medium to pass two selected landmarks on the angiograms also significantly decreased (41 +/- 17 frames to 18 +/- 8 frames, p= 0.0039). Thus intracoronary papaverine attenuated angiographic no-reflow that occurred after PTCA for AMI.

Adult↗
PubMed1996

[Efficacy and limitation of directional coronary atherectomy for acute myocardial infarction assessed by depth of tissue resection].

The efficacy and limitations of directional coronary atherectomy (DCA) for acute myocardial infarction were evaluated in 44 patients (left anterior descending artery : 27 lesions, left circumflex artery : 2 lesions, right coronary artery : 15 lesions) who underwent DCA within 24 hours after the onset of chest pain. Thirty-two patients underwent DCA for residual stenosis of > or = 75% with TIMI flow grade II or III after thrombolysis (immediate DCA), and 12 patients underwent DCA for suboptimal results after immediate percutaneous transluminal coronary angioplasty (rescue DCA). In all patients, DCA resulted in residual stenosis of <25% (15 +/- 8%), and the primary success rate was 100%. No major complications (death, emergency bypass grafting) occurred. Repeat angiography was performed in 41 patients before discharge (2.4 +/- 0.7 weeks later) and in 39 patients during follow-up (5 +/- 2 months later). Reocclusion was not found at the follow-up. Restenosis was not found before predischarge, but was found in 19 of the 39 patients (49%) at the follow-up. Histological analysis of atheroma samples was performed to evaluate the influence of subintimal resection on restenosis. Patients were divided into two groups according to the depth of tissue resection : intimal resection and subintimal resection. The restenosis rate associated with subintimal resection was significantly higher than that associated with intimal resection (80% vs 29%, p < 0.01). DCA is useful for persistent patency of the infarct-related coronary artery in patients with acute infarction, but subintimal resection may increase the restenosis rate during the follow-up period.

Adult↗
PubMed1996

[Evaluation of occult atherosclerosis in the left main coronary artery in patients with acute anterior myocardial infarction].

Intravascular ultrasound was performed in 30 patients with acute anterior myocardial infarction to evaluate occult atherosclerosis in the left main coronary artery which could not be detected by coronary angiography. The intravascular ultrasound catheter was positioned in the left main coronary artery after successful intracoronary thrombolysis, and cross-sectional coronary artery scanning was performed. Percentage area stenosis (%AS) was calculated as (plaque cross-sectional area/vessel cross-sectional area) x 100. Images of crescent-shaped eccentric plaque were obtained in all patients. The mean vessel cross-sectional area was 28.6 +/- 8.0 mm2, and mean plaque cross-sectional area was 7.7 +/- 4.2 mm2. Mean %AS was 27 +/- 15% (range from 6 to 58%). In five patients, intravascular ultrasound was repeated 3 months later, which showed increased %AS more than 15% in two patients. These findings indicate that occult atherosclerosis is present in the left main coronary artery in almost all the patients with acute anterior myocardial infarction and should be treated with caution when coronary intervention is performed.

Adult↗
PubMed1995

Novel muteins of human tumor necrosis factor with potent antitumor activity and less lethal toxicity in mice.

Eight muteins of recombinant human tumor necrosis factor-alpha (rhTNF; 1SSSRTP...29RR...155L), in which 29Arg was replaced by another amino acid, were prepared and their anti-tumor effects in BALB/c mice bearing Meth A fibrosarcoma were evaluated. The therapeutic indices, which mark the extent of the therapeutically effective dose, of V29 (29Arg-->Val) and D29 (-->Asp) were 3.5 and 3.2, respectively, whereas that of rhTNF was 1.4. Clearly, the therapeutically effective range of these muteins was extended along with a decrease in lethal toxicity. V29 did not produce hypotension in the rat system, but D29 did. In addition, V29 showed potent anti-tumor activity (Tumor Volume Inhibition Rate = 81% on day 15 after implantation) in 3 consecutive injection schedules despite the decreases in toxicity compared with rhTNF. The relative receptor binding constant was determined using HEp-2 cells (expressing mainly 55-kDa-TNF receptor; p55R) and HL60 cells (expressing mainly 75-kDa-TNF receptor; p75R), and revealed that the reduced toxicity of V29 in mice was due to the reduced binding to p55R (34% of rhTNF). On the other hand, the ratio of the constants HEp-2/HL60 of V29 was 11 in comparison with the value of 1.0 for rhTNF, suggesting that this mutein binds preferentially to p55R. The biological activities in human cell lines (HEp-2 and HL60 cells) correlated well with the binding activities to each receptor in vitro. Therefore, the much lower toxicity and the potent anti-tumor activity of this mutein suggest that V29 merits further investigation in pre-clinical and clinical trials.

Amino Acid Sequence↗
PubMed1995

Effects of various doses of intracoronary diltiazem on coronary resistance vessels in humans.

We investigated the vasodilative effects of various doses of intracoronary diltiazem on coronary resistance vessels. Nine patients with normal angiograms were studied. A coronary Doppler guide wire was inserted into the left anterior descending coronary artery. Diltiazem, in doses of 0.1 mg, 0.5 mg, 1.0 mg, 2.0 mg and 4.0 mg, was injected into the left coronary artery at 10 min intervals and coronary blood flow velocity was measured. The coronary artery was pretreated with intracoronary nitroglycerin to avoid changes in the cross-sectional area. As a measure of the change in coronary vascular resistance, a coronary vascular resistance index (CVRI) was calculated as mean aortic pressure/coronary blood flow velocity. An injection of diltiazem into the left coronary artery caused a significant dose-dependent decrease in CVRI. A dose of 2.0 mg was the lowest dose on the plateau of the dose-response curve. In conclusion, the injection of diltiazem into the left coronary artery causes a dose-dependent dilatation of coronary resistance vessels, and the maximal effect can be produced with a dose of 2.0 mg.

Aged↗
PubMed1995

The role of the left atrial appendage. A volume loading study in open-chest dogs.

Although the left atrial appendage has a quite unique structure, its function remains unclear. To clarify the function of the left atrial appendage, changes in its anteroposterior, transverse and longitudinal dimensions, and in the anteroposterior dimension of the left atrial body were measured by a sonomicrometer during volume loading in open chest dogs. In the control state, fractional shortening of the transverse dimension of the appendage was greater than that of the atrial body. After dextran infusion, each dimension of the appendage and body, measured just before atrial contraction, increased curvilinearly. The percent increase in appendage dimensions was greater than that of the atrial body dimension (p < 0.05). Systolic shortenings of the appendage increased until mean left atrial pressure reached approximately 15 mmHg but after further pressure elevation, it decreased. In postmortem isolated hearts, the appendage volume was 17.2 +/- 4.4% of the whole left atrial volume. These findings indicate that the appendage has a considerable volume with a greater compliance and assists left ventricular filling during atrial contraction by a Frank-Starling mechanism.

Animals↗