Biomedical subjects

S Muraki

Publications and source records attributed to S Muraki.

At least 19 recordsLinked to original sources

PubMed2003

[Utility of the perfusion-assist for beating heart coronary artery bypass surgery].

During off-pump coronary artery bypass surgery, concern remains about the possible myocardial injury associated with the transient occlusion and stabilization of the target vessels. To try to minimize myocardial ischemia and achieve hemodynamic stability, we utilized a coronary perfusion catheter combined with the perfusion-assisted direct coronary artery bypass system that enables active and modified coronary perfusion of the target vessel throughout the duration of multiple grafting (modified PADCAB). In the series of 10 patients, perfusion of the target coronary systems averaged 2,072.8 +/- 649.7 ml over 92.9 +/- 26.1 minutes under a constant infusion pressure of 120 mmHg. Nitroglycerin (100 micrograms/l of flow) was delivered directly into the coronary arteries as an additive in all patients. Hemodynamic instability was notably absent in all cases, even in cases that required difficult anastomosis with a relatively long time for the anastomosis. There were no perioperative complications and no detectable myocardial damage (i.e., impairment of myocardial wall motion indicated by echocardiography findings or by > 0.25 ng/ml of troponin-T release compared to the preoperative level) in this series of patients.

Aged↗

PubMed2002

[Minimal incision abdominal aortic aneurysm repair].

OBJECTIVE: The use of a limited incision for abdominal aortic aneurysm (AAA) repair was evaluated, and its outcome was analyzed in comparison to standard open repair. PATIENTS AND METHODS: Between February 2000 and August 2001, 20 patients with an AAA underwent minimal incision repair (MINI) for tube graft implantation. The minimal skin incision was made after localization of aneurysm neck and aortic bifurcation by CT and DSA. For repair of the upper part of the AAA the abdominal incision was retracted toward the head of the patient who was in a jackknife decubitus position. Conversely, when the peripheral portion of the AAA was treated, the abdominal incision was retracted caudally with the patient in a flat or slightly bent decubitus position. The operation itself was performed using the standard conventional technique. The length of the abdominal incision was 10 cm. Clinical characteristics and in-hospital outcome of this procedure were compared to a group of patients who underwent repair of AAA by means of a standard open technique (OPEN). RESULTS: Patients age in the MINI and OPEN groups were similar (69 +/- 11 vs. 69 +/- 9 years). However, there were significant differences between the MINI and OPEN groups in the time for starting oral intake of food (2,4 +/- 1,2 vs. 7,4 +/- 5,5 postoperative days, p = 0,003), time for starting to walk outside the room (2,2 +/- 0,7 vs. 4,6 +/- 2,2 postoperative days, p = 0,01) and operation times (197 +/- 37 vs. 294 +/- 83 min, p = 0,0004). CONCLUSION: Minimal incision repair is technically feasible and combines the benefits of a minimal incision with those of conventional open repair, reducing patient recovery time.

Aged↗

PubMed2002

[Antegrade selective cerebral perfusion for extended total arch replacement using separated graft technique; reassessment from the type of aneurysms and dissections].

One hundred eighty two patients with thoracic aortic aneurysms or dissections who required total arch replacement (TAR) were operated on with separated graft technique and selective cerebral perfusion (SCP) between 1991 and 2000. These patients were divided into 4 groups according to the pathology as follows: group 1; acute type A dissection, group 2; chronic type A dissection, group 3; distal arch aneurysm and group 4; proximal arch aneurysm. For SCP, both the innominate artery and the left common carotid artery were cannulated when the patient was cooled to a rectal temperature of 22 degrees C. Hospital mortalities were 27% in group 1, 14% in group 2, 19% in group 3, and 8% in group 4. Independent predictors of hospital mortality were shock, visceral, and leg ischemia in group 1, and circulatory arrest time of the lower half body to be more than 1 hour and cardiopulmonary bypass time to be more than 5 hours in group 3. Permanent neurological complication occurred in 3% in group 1 and 8% in group 3. Hospital mortality was affected by the type of aneurysms and dissections. It is necessary to give careful consideration to the indication of TAR with SCP, especially in acute type A dissection and distal arch aneurysm.

Aged↗

PubMed2001

Retinotopic hemodynamic activation of the human V5/MT area during optokinetic responses.

To detect retinotopic activation in the human V5/MT, we obtained fMRI signals during optokinetic responses (OKR). We used two types of patterns, consisting of random dots plotted in either the central or peripheral regions, to stimulate the central and peripheral visual fields, respectively. These patterns moved at a constant speed of 20 degrees/s rightward and leftward alternately. Subjects were required to track the patterns with their eyes. The two types of visual stimuli elicited different patterns of brain activation; the area with the most significant response to central visual field stimuli was located posteriorly to that responding to peripheral visual field stimuli.

Adult↗

PubMed2001

All-blood (miniplegia) versus dilute cardioplegia in experimental surgical revascularization of evolving infarction.

BACKGROUND: The advantages of blood cardioplegia include the oxygen-carrying capacity, superior oncotic and buffering properties, and endogenous antioxidants contained in blood. However, the partial dilution of blood in 4:1 (blood:crystalloid) cardioplegic solutions may nullify these advantages and progressively dilute blood during continuous retrograde delivery. This study tested the hypothesis that all-blood (66:1) cardioplegia provides superior myocardial protection compared with dilute (4:1) cardioplegia delivered in a continuous retrograde modality during surgical reperfusion of evolving myocardial infarction. METHODS AND RESULTS: After 60 minutes of left anterior descending coronary artery (LAD) occlusion, anesthetized canines were placed on cardiopulmonary bypass and randomized to either all-blood cardioplegia (AB group) or dilute blood cardioplegia (Dil group). After cross clamping, arrest was induced with 5 minutes of tepid (30 degrees C) antegrade potassium all-blood or dilute blood cardioplegia and maintained with tepid retrograde coronary sinus cardioplegia for a total of 1 hour. The LAD was released after 30 minutes of arrest, simulating revascularization. The cardioplegia hematocrit for the Dil group was lower than that for the AB group (7+/-1% versus 12+/-2%, P<0.05); at the end of bypass, systemic hematocrit was lower in the Dil group than in the Ab group (15+/-1% versus 20+/-1%, P<0.05). Infarct size (triphenyltetrazolium chloride staining) was comparable between the AB and Dil groups (29.6+/-2.9% versus 30.3+/-3.9% of area at risk), and there was no difference in area-at-risk myocardium systolic shortening (by sonomicrometry, -0.3+/-1% versus -0.4+/-1%). Tissue edema after bypass tended to be greater in the Dil group compared with the AB group in the heart (82+/-0% versus 81+/-1%), lung (79+/-1% versus 78+/-1%), liver (75+/-1% versus 74+/-0%), and skeletal muscle (76+/-1% versus 73+/-2%) and was significantly greater in the duodenum (80+/-1% versus 79+/-1%, P<0.05) and kidney (82+/-1% versus 79+/-1%, P<0.05). Postexperimental endothelial function (relaxation of acetylcholine) was impaired in LADs of the AB group versus the Dil group (59+/-6% versus 77+/-5%, P<0.05). CONCLUSIONS: Both all-blood cardioplegia and dilute cardioplegia have disadvantages, but these do not have an impact on the pathogenesis of infarct size or recovery of regional contractile function.

Animals↗

PubMed2001

Adenosine attenuates reperfusion-induced apoptotic cell death by modulating expression of Bcl-2 and Bax proteins.

This study tests the hypothesis that infarct reduction with adenosine (Ado) is associated with inhibition of apoptotic cell death by modulating expression of anti-apoptotic Bcl-2 and pro-apoptotic Bax proteins and reducing neutrophil accumulation. In three groups of dogs, the left anterior descending coronary artery was occluded for 60 min and reperfused for 6 h. Either saline (Control, n=8), Ado (140 microg/kg/min, n=8) or CGS21680, an adenosine A2A receptor analogue, (0.2 microg/kg/min, n=7) were infused during the first 2 h of reperfusion. Myocardial apoptosis was detected by histological TUNEL staining and DNA laddering. Expression of Bcl-2 and Bax proteins was analyzed using Western blot assay. Neutrophil localization was detected by immunohistochemistry with monoclonal anti-neutrophil CD18 antibody. There was no group difference in collateral blood flow (colored microspheres) during ischemia. Intra-left atrial administration of Ado and CGS21680 significantly decreased infarct size from 26+/-2% in Control to 13+/-1%* and 16+/-3%*, respectively. TUNEL positive cells in the peri-necrotic zone of the ischemic myocardium were also significantly reduced from 16+/-2% in Control group to 9+/-1%* and 10+/-2%*, respectively, consistent with the absence of DNA laddering in these two groups. Densitometrically, Ado and CGS21680 at reperfusion significantly increased the expression (% of normal myocardium) of downregulated Bcl-2 from 45+/-6% in Control group to 78+/-12%* and 69+/-10%*, respectively, and attenuated expression of upregulated Bax from 198+/-16% in Control group to 148+/-10%* and 158+/-12%*, respectively. Furthermore, the number of positive CD18 cells (mm(2) myocardium), which was significantly correlated with TUNEL positive cells in peri-necrotic zone, was significantly reduced from 403+/-42 in Control group to 142+/-18* in Ado group and 153+/-20%* in CGS21680 group, respectively. In conclusion, the present study suggests that inhibition of apoptosis by Ado at reperfusion involves alterations in anti-apoptotic Bcl-2 and pro-apoptotic Bax proteins and neutrophil accumulation, primarily mediated by an adenosine A2A receptor. * P<0.05 v Control group.

Adenosine↗

PubMed2001

Decrease in the Ca2+-activated K+ current of pulmonary arterial smooth muscle in pulmonary hypertension rats.

Pulmonary hypertension exhibits acute elevation of vascular tone and hyperreactivity of pulmonary vasculature, which are closely related to patient mortality. In the present study, we investigated the characteristics of membrane currents of isolated pulmonary artery smooth muscle cells taken from rats with monocrotaline-induced pulmonary hypertension. Male Wistar rats were given a single subcutaneous injection of monocrotaline or saline, and then sacrificed between 18 to 21 days after the injection. The membrane currents in the smooth muscle cells from both groups of rats were compared using the whole-cell patch clamp technique. With 0.1 mM EGTA in the pipette, the densities of outward currents in monocrotaline-injected rats were smaller than those in control rats. When EGTA in patch pipettes was increased to 10 mM, the densities of the outward currents in monocrotaline-injected rats were equal to those of control rats. The Ca2+-activated K+ channel blockers (TEA, iberiotoxin) and nisoldipine were less effective on the outward currents of monocrotaline-injected rats. In the current clamp mode, a depolarization of membrane potential induced by 4-aminopyridine was greater in monocrotaline-injected rats than in control rats because of the reduced activity of the Ca2+-activated K+ channels. The Ca2+-activated K+ channels were decreased in pulmonary hypertension. The reduced activity of the currents may be related to the vascular hyperreactivity in pulmonary hypertension.

Analysis of Variance↗

PubMed2001

Electroplegia: an alternative to blood cardioplegia for arresting the heart during conventional (on-pump) cardiac operation.

BACKGROUND: Aortic cross-clamping is contraindicated in patients with severe atherosclerosis of the ascending aorta, and administration of chemical cardioplegia may be cumbersome in these patients. In this study, we demonstrate an alternative method of achieving cardioplegia by electrical stimulation of the vagus nerve. METHODS: In anesthetized canines, the left anterior descending coronary artery was reversibly ligated for 90 minutes, followed by cardiopulmonary bypass (CPB) and randomization to three groups (n = 8 each): (1) BCP group: 1 hour of intermittent hypothermic (4 degrees C) blood cardioplegia infusion; (2) CPB group: 1 hour of CPB alone; (3) EP group (group receiving electroplegia): 1 hour of intermittent vagal stimulation (total of 60 20-second electrical stimuli at 40 Hz, 6 to 10 V) with adjunctive pyridostigmine (0.5 mg/kg), verapamil (50 microg/kg), and propranolol (80 microg/kg) to potentiate hyperpolarization and suppress ectopic escape beats. RESULTS: The EP group achieved consistent intervals of arrest with 3.8 +/- 1.2 escape beats per 20-second stimulation period. After 2 hours of reperfusion off CPB, the left anterior descending coronary artery segmental shortening was reduced from baseline in all groups, but the segmental shortening recovered to a greater extent in the EP group than in either the CPB or BCP group (2.4% +/- 1.4% versus -1.3% +/- 1.3% versus -4.0% +/- 0.8%, p < 0.05). Infarct size (TTC stain, percentage of area at risk) was comparable among groups (EP: 20.9% +/- 4.7%; CPB: 29.6% +/- 3.2%; BCP: 25.1% +/- 5.7%). Postischemic left anterior descending coronary artery endothelial function (percent maximum relaxation to acetylcholine) was depressed in the EP group (68.6% +/- 7.6% versus 102.3% +/- 6.4%, p < 0.05), but was comparable versus nonischemic circumflex function in the BCP group (77.1% +/- 11.9% versus 100.4% +/- 10.0%, p = 0.15) and the CPB group (93.8% +/- 6.6% versus 93.3% +/- 6.6%). CONCLUSIONS: Electroplegia achieves elective intermittent cardiac arrest, avoids hypothermia, chemical cardioplegia, and aortic cross-clamping, with physiological outcomes comparable to blood cardioplegia.

Acetylcholine↗

PubMed2001

Brief pretreatment of radial artery conduits with phenoxybenzamine prevents vasoconstriction long term.

BACKGROUND: Radial artery bypass conduits are prone to early vasospasm or "string sign" with use of vasopressor therapy intraoperatively and postoperatively, causing increased resistance in coronary artery grafts. Current intraoperative treatment with papaverine fails to provide sustained inhibition of vasoconstriction. We tested the hypothesis that a 30-minute pretreatment of radial artery segments with the alpha-adrenergic antagonist phenoxybenzamine (PB) or the putative protein phosphatase 2,3-butadione monoxime (BDM) attenuates vasoconstriction induced by the vasopressors phenylephrine or norepinephrine for as long as 48 hours compared with papaverine. METHODS: Canine radial arteries were harvested, incubated in control buffer or solutions of papaverine 10(-6) M, BDM 10(-6) M or phenoxybenzamine 10(-6) M for 30 minutes, washed, and stored in drug-free culture medium for 2, 24, or 48 hours. After storage, constriction was induced by norepinephrine at incremental concentrations ranging from 0.7 to 3.5 micromol/L or by phenylephrine (0.300 to 1.5 micromol/L) with or without the inhibitors, and the degree of vasoconstriction was quantified in organ chambers. Responses to norepinephrine or phenylephrine were compared to constriction with receptor-independent potassium chloride KC1 (30 mmol/L). RESULTS: Maximum responses to phenylephrine and norepinephrine were comparable at 2, 24, and 48 hours after harvest in the control group (phenylephrine: 67% +/- 4%, 62% +/- 6%, 65% +/- 6% of KC1 response; norepinephrine: 75% +/- 4%, 62% +/- 1%, 58% +/- 7%, respectively). Papaverine failed to attenuate constriction to phenylephrine and norepinephrine 2, 24, or 48 hours posttreatment. Pretreatment with BDM did not reduce vasoconstriction responses to phenylephrine or norepinephrine 2 hours after incubation but did reduce constriction responses thereafter. In contrast, phenoxybenzamine completely attenuated constriction to both phenylephrine (19% +/- 8%, 1% +/- 4%, -12% +/- 4%) and norepinephrine (7.1% +/- 1%, -5% +/- 5%, -20% +/- 5%) at 2, 24, and 48 hours posttreatment, respectively. Phenoxybenzamine did not alter endothelial function relative to controls at any time point. CONCLUSIONS: Thirty-minute pretreatment of RA conduits with 10(-6) M phenoxybenzamine completely inhibits vasoconstriction to phenylephrine and norepinephrine for as long as 48 hours. Soaking radial artery grafts briefly in phenoxybenzamine solution before implantation may be effective in preventing postoperative vasospasm caused by two common alpha-adrenergic agonists used in postoperative hemodynamic management.

Animals↗

PubMed2001

Myocardial protection for off-pump coronary artery bypass surgery.

Myocardial protection during off-pump coronary artery bypass surgery (OPCAB) is a multifactorial problem. Careful, individualized choice of graft sequence and maintenance of stable systemic hemodynamics are of central importance. Recently refined techniques for atraumatic rotation of the heart and visualization of coronary anastomoses allow precise and controlled grafting of all coronary territories without cardiopulmonary bypass in the large majority of cases. Perfusion-assisted direct coronary artery bypass (PADCAB) techniques, in which coronary perfusion pressure is independent of systemic arterial pressure, can avoid or abort a downward hemodynamic spiral, which may occasionally occur during complex, multivessel OPCAB. PADCAB promotes collateral myocardial perfusion and avoids the cumulative global effect of sequential episodes of regional ischemia, improving myocardial protection during OPCAB.

Anastomosis, Surgical↗

PubMed2001

Experimental off-pump coronary artery revascularization with adenosine-enhanced reperfusion.

OBJECTIVE: Although beating heart coronary artery bypass grafting has recently gained popularity, it eliminates the protective strategies (ie, cardioplegia) developed for use in conventional cardiac operations. We recently introduced the technique of perfusion-assisted direct coronary artery bypass to perfuse the grafted vessels during multivessel off-pump coronary artery bypass grafting. In the present study we tested the hypothesis that intracoronary reperfusion with the cardioprotective agent adenosine during simulated perfusion-assisted direct coronary artery bypass attenuates reperfusion injury. METHODS: In anesthetized dogs the heart was exposed, and the left anterior descending coronary artery was ligated for 75 minutes. Reperfusion was achieved through a catheter in the left anterior descending coronary artery by means of a computer-controlled pump. Intracoronary left anterior descending coronary artery perfusion pressure was continuously matched to mean arterial blood pressure. In one group (adenosine group) 10 micromol/L adenosine was added to the blood during the first 30 minutes of reperfusion, whereas another group (vehicle group) received a comparable volume of saline solution. RESULTS: During the first 30 minutes of reperfusion, blood flow through the left anterior descending coronary artery was significantly greater (P <.05) in the adenosine group than in the vehicle group (150.6 +/- 21.9 vs 50.2 +/- 11.3 mL/min at 15 minutes of reperfusion). Although there were no group differences in postischemic wall motion, infarct size was significantly smaller in the adenosine group than in the vehicle group (11.1% +/- 3.0% vs. 28.0% +/- 4.0% of area at risk, P <.05). Myeloperoxidase activity in the necrotic tissue, an index of neutrophil accumulation, tended to be lower in the adenosine group than in the vehicle group (58.6 +/- 14.2 vs. 91.0 +/- 21.6 DeltaAbs Units x min(-1) x g(-1) tissue). In isolated postischemic left anterior descending coronary artery rings, the maximal relaxation response to the endothelium-dependent vasodilator acetylcholine was significantly greater in the adenosine group than in the vehicle group (97.9% +/- 5.6% vs. 64.7% +/- 6.5%, P<.05). CONCLUSION: This novel reperfusion strategy for off-pump coronary artery bypass grafting can be used not only in cases requiring multiple grafting but also to attenuate necrosis and endothelial dysfunction in acute evolving infarction.

Adenosine↗

PubMed2001

Characteristics of body heat balance of paraplegics during exercise in a hot environment.

The purpose of this investigation was to clarify the characteristics of body temperature regulation in paraplegics due to spinal cord injury (SCI) during an arm cranking exercise in a hot environment. Twelve paraplegics with lesions located between Th3 and L1,2 and seven able-bodied subjects (AB) participated in this study. The subjects were exposed to a hot (33 degrees C) or a moderate temperature (25 degrees C) environment for one hour and during the last 10 min of the exposure, the subjects performed arm cranking exercises at an exercise intensity of 40 W. The skin temperatures at the chest, the upper arm, the thigh and the calf, the tympanic membrane temperature (Tty), and the skin blood flow of the thigh (SBFT) were continuously monitored during the experiment. Although no systematical variation was found in the Tty at 25 degrees C, the Tty at 33 degrees C in paraplegics during exercise was significantly greater than that at rest (P < 0.01), which indicated a pronounced heat stress for paraplegics at 33 degrees C. SBFT of paraplegics with high lesions of the SCI remained unchanged during the experiment at 25 degrees C and 33 degrees C, while paraplegics with low lesions in this study showed consecutive increases in SBFT during exercise in both environmental conditions similar to AB. The increased core temperature in paraplegics with high lesions was considered to be due to a lack of sweat response and vasomotor activity in the paralyzed area. On the basis of the findings in this study, it can be suggested that high core temperature without any increment of SBFT may be characterized as body heat balance of paraplegics with high lesions during exercise in a hot environment.

Adult↗

PubMed2001

[Development of three-dimensional stereo viewer for high-resolution data].

In order to visualize high-resolution three-dimensional (3D) data as a stereogram, a real-time volume-rendering system using a hardware graphic board and conventional PC was developed. A 256(3) data set could be visualized at a redrawing rate of 12 Hz, and a 512(3) data set at a rate of 2.5 Hz. It was demonstrated that stereogram visualization using volume graphic hardware architecture potentially enables rapid examination of high-resolution 3D data by changing visualization parameters such as level, window, transfer function for opacity, and color map or coordinate direction.

Computer Graphics↗

PubMed2000

Multivariate analysis of factors influencing physical work capacity in wheelchair-dependent paraplegics with spinal cord injury.

The purpose of this study was to determine the main factors that influence physical work capacity (PWC) in wheelchair-dependent paraplegics with spinal cord injury (SCI) using multivariate analysis. Thirty-two male paraplegics with SCI (PSCI) performed a submaximal arm exercise test on an arm-cranking ergometer to determine their PWC (oxygen uptake: ml x kg(-1) x min(-1)) at a heart rate of 150 beats x min(-1) (PWC150). Hayashi's Quantification first type was applied to analyze the effects on PWC150 of six factors: age, smoking, level of physical activity, occupation, level of SCI and period since SCI. This analysis revealed high partial correlation coefficients between PWC150 and the level of SCI (0.651) and physical activity level (0.583) compared to other factors. In addition, the multiple correlation coefficient for six factors in predicting PWC150 was 0.726. These results indicate that the level of SCI and physical activity are the most important factors in determining PWC in wheelchair-dependent male PSCI.

Adult↗

PubMed2000

Cardiovascular responses at the onset of passive leg cycle exercise in paraplegics with spinal cord injury.

The purpose of this study was to examine the cardiovascular responses at the onset of passive leg cycle exercise (PLCE) in paraplegics with spinal cord injury (PSCI) to investigate the increase in venous return from the paralyzed lower limbs during PLCE. Six male PSCI having lesions at levels ranging from T8 to L1 and five male able-bodied subjects (ABS) participated in this study. The subjects performed PLCE at pedalling frequencies of 40 rpm for 6 min. Cardiac output (Q(c)), stroke volume (SV) and heart rate (f(c)) were measured before and during PLCE. In the steady state (4th and 5th min) of PLCE, both PSCI and ABS showed a significant increase in Q(c). At the onset of PLCE, however, clear differences in the cardiovascular response were found between PSCI and ABS. The ABS showed a rapid and marked increase in f(c) and consequently Q(c) within 20 s of the onset of PLCE. On the other hand, in PSCI, the Q(c) increased more slowly, compared with that in ABS, because of a smaller increase in f(c) and a delayed increase in SV. The observed delay in the increases of Q(c) and SV at the onset of PLCE in PSCI was presumably due to the absence of afferent reflexes from the lower limbs, and to the additional time needed for venous return to arrive at the heart from the passively moved muscles.

Adult↗

PubMed2000

Comparative study of AMP579 and adenosine in inhibition of neutrophil-mediated vascular and myocardial injury during 24 h of reperfusion.

OBJECTIVE: The purpose of this study was to compare protective effects of AMP579 and adenosine (Ado) at reperfusion (R) on inhibition of polymorphonuclear neutrophil (PMN) activation, PMN-mediated injury to coronary artery endothelium, and final infarct size. METHODS: In anesthetized dogs, 1 h of left anterior descending coronary artery occlusion was followed by 24 h R and drugs were administered at R. Control (n=8, saline control), AMPI (n=7, AMP579, 50 microg/kg i.v. bolus followed by 3 microg/kg/min for 2 h), AMPII (n=7, AMP579, 50 microg/kg i.v. bolus), AMPIII (n=7, AMP579, 3 microg/kg/min i.v. for 2 h), and Ado (n=7, adenosine, 140 microg/kg/min i.v. for 2 h). RESULTS: AMP579 in vitro directly inhibited superoxide radical (O(-)(2)) generation (nM/5x10(6) PMNs) from PMNs dose-dependently (from 17+/-1* at 10 nM to 2+/-0.2* at 10 microM vs. activated 30+/-2). However, inhibition of O(-)(2) generation by Ado at each concentration was significantly less than for AMP579. The IC(50) value for AMP579 (0.09+/-0.02 microM) on O(-)(2) generation was significantly less than that of Ado (3.9+/-1. 1 microM). Adherence of unstimulated PMN to postischemic coronary artery endothelium (PMNs/mm(2)) was attenuated in AMPI and AMPIII vs. Control (60+/-3* and 58+/-3* vs. Control 110+/-4), while Ado partially attenuated PMN adherence (98+/-3*). Accordingly, endothelial-dependent vascular relaxation was significantly greater in AMPI and AMPIII vs. Ado. At 24 h R, myocardial blood flow (MBF, ml/min/g) in the area at risk (AAR), confirmed by colored microspheres, in AMPI and AMPIII was significantly improved (0.8+/-0. 1* and 0.7+/-0.1* vs. Control 0.3+/-0.04). Infarct size (IS, TTC staining) in AMPI and AMPIII was significantly reduced from 38+/-3% in Control to 21+/-4%* and 22+/-3%*, respectively, confirmed by lower plasma creatine kinase activity (I.U./g protein) in these two groups (27+/-6* and 32+/-2* vs. 49+/-3). Cardiac myeloperoxidase activity (MPO, Abs/min) in the AAR was significantly reduced in AMPI and AMPIII vs. Control (36+/-11* and 35+/-10* vs. 89+/-10). However, changes in MBF, IS and MPO were not significantly altered by Ado. CONCLUSIONS: These data suggest that continuous infusion of AMP579 at R is more potent than adenosine in attenuating R injury, and AMP579-induced cardioprotection involves inhibition of PMN-induced vascular and myocardial tissue injury. *P<0.05 vs. Control.

Adenosine↗

PubMed2000

Effect of acute heat exposure on skin blood flow of the paralyzed thigh in persons with spinal cord injury.

OBJECTIVES: To investigate whether increased body temperature during heat exposure promotes skin blood flow of the thigh (SBFT) in individuals with spinal cord injury at rest. STUDY DESIGN: A prospective study with high lesion and with low lesion. SETTING: Hiroshima University, Higashi-Hiroshima, Japan. METHODS: Seven male paraplegics (T5-L2) and seven able-bodied subjects volunteered to participate in the experiment. First the subject rested for 1 h at an ambient temperature (Ta) of 25 degrees C and a relative humidity (Rh) of 50%. Thereafter, the subject moved to a climatic chamber heated to Ta of 33 degrees C an Rh of 50 - 55% and was exposed to this environment for 1 h. SBFT, stroke volume, heart rate, the skin temperature of the medial thigh (Tthigh) and the tympanic membrane temperature (Tty) were assessed during the experiment. RESULTS: The four subjects with high lesions between Th6 and Th10 (HL) showed no increase in SBFT, while the remaining three subjects with low lesion at Th11 or Th12 (LL) showed increased SBFT in the hot environment. Although Tty increased with exposure time in heat, correlation between Tty and SBFT was not significant in either paraplegic group. However, correlation between SBFT and Tthigh was highly significant in both groups. The increase in Tthigh in LL was due to increased skin blood flow in the thigh, while in HL it was considered attributable to heat transfer from the environment to the skin. CONCLUSION: These findings indicate that SBFT during heat exposure was largely dependent on the level of spinal cord injury. SBFT with low lesions increased during heat exposure when the sympathetic cutaneous vasomotor supply of the thigh was preserved.

Adult↗

PubMed2000

The effect of frequency and mode of sports activity on the psychological status in tetraplegics and paraplegics.

OBJECTIVE: To examine whether the psychological benefits of sports activity differ between tetraplegics and paraplegics with spinal cord injury, and investigate the effect of frequency and modes of sports activity on the psychological benefits. METHODS: The Self-rating Depression Scale (SDS), State-Trait Anxiety Inventory (STAI) and Profiles of Mood States (POMS) were administered to 169 male individuals with spinal cord injury (mean age=42.7 years) including 53 tetraplegics and 116 paraplegics. The subjects were divided into four groups according to their frequencies of sports activity; High-active (more than three times a week; n=32), Middle-active (once or twice a week, n=41), Low-active (once to three times a month, n=32), and Inactive (no sports participation, n=64). RESULTS: Analysis of variance revealed significant differences in depression for SDS, trait anxiety for STAI and depression and vigor for POMS among the groups. High-active group showed the lowest scores of depression and trait anxiety and the highest score of vigor among the four groups. In contrast, no significant difference was found for any psychological measurements between tetraplegics and paraplegics. In addition, there was no significant difference for any psychological measurements among modes (wheelchair basketball, wheelchair racing, wheelchair tennis and minor modes). CONCLUSIONS: These findings demonstrated that sports activity can improve the psychological status, irrespective of tetraplegics and paraplegics, and that the psychological benefits are emphasized by sports activity at high frequency.

Adolescent↗