Biomedical subjects

T Yada

Publications and source records attributed to T Yada.

At least 19 recordsLinked to original sources

PubMed1992

Isolation and characterization of type IX collagen-proteoglycan from the Swarm rat chondrosarcoma.

Type IX collagen was partially purified from the Swarm rat chondrosarcoma by a series of a conventional salting-out procedures. The preparation was further separated by anion exchange chromatography into an unbound and a bound fraction in an A230 ratio of about 5:1. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the bound fraction appeared as a broad band, whose molecular mass ranged from 250 to 270 kDa. Digestion with chondroitinase ABC reduced the apparent molecular mass of the bound fraction to about 250 kDa, a value comparable to the molecular mass of the unbound fraction. Tryptic peptide maps of the protein moieties of unbound and bound forms showed that their molecular structures were basically identical. A monoclonal antibody specific for LMW, one of the pepsin-resistant fragments of the rat sarcoma type IX, reacted with both the unbound and bound fractions. Together the results indicate that the unbound and bound fractions represent a type IX collagen devoid of the chondroitin sulfate chain and its proteoglycan form with covalently bound chondroitin sulfate, respectively. The extent of glycosaminoglycan attachment to type IX collagen molecules in rat chondrosarcoma (about 16%) is quite different from the extents described in chick embryo cartilage (about 80%), chick vitreous humour (100%) and bovine cartilage (less than 5%). Further studies on the neoplastic tissue will offer additional information regarding the biological basis and biological consequences of the glycosaminoglycan attachment to type IX collagen molecules.

Animals↗

PubMed1992

Changes in growth hormone and prolactin messenger ribonucleic acid levels during seawater adaptation of amago salmon (Oncorhynchus rhodurus).

To examine the changes in secretion of growth hormone (GH) and prolactin (PRL) with reference to their osmoregulatory roles, changes in pituitary mRNA levels and plasma concentrations of these hormones were examined during seawater adaptation in silvery juveniles (smolts) and precociously mature males (dark parr) of amago salmon (Oncorhynchus rhodurus). Transfer to seawater increased plasma sodium levels in both smolts and dark parr. Smolts adjusted their plasma sodium to the level associated with seawater-adaptation (165 mEq/liter) within 3 days, whereas no adjustment was seen in dark parr; the latter failed to survive in seawater for more than 3 days. In smolts, plasma GH levels increased significantly 1 day after transfer, whereas there was no significant change in dark parr. An increase in GH mRNA levels was observed in smolts in association with increased plasma GH, whereas there was no change in dark parr. In contrast, a reduction in plasma PRL levels was consistently observed in both smolts and dark parr after transfer to seawater. However, there was no significant change in PRL mRNA levels in either smolts or dark parr. These results suggest that both gene expression and release of GH are activated by seawater transfer only in smolts with adequate seawater adaptability, whereas PRL gene expression is decreased after seawater transfer regardless of seawater adaptability.

Adaptation, Physiological↗

PubMed1992

Occurrence of collagen and proteoglycan forms of type IX collagen in chick embryo cartilage. Production and characterization of a collagen form-specific antibody.

Type IX collagen from chick embryonic cartilage is a proteoglycan bearing a single chondroitin sulfate chain covalently linked to the alpha 2(IX) polypeptide chain. We have isolated type IX collagen metabolically labeled with [3H]proline using an antibody to type IX collagen and have found that the molecule is synthesized in two forms, a collagen form (COLIX) and a proteoglycan form (PGIX). In cultured chondrocytes, the two forms of type IX collagen showed a different ability to be deposited in the matrix. We have suggested the possibility that both forms may arise from an alternative substitution of a chondroitin sulfate chain to the NC3 domain of the alpha 2(IX) chain. Based on the reported amino acid sequence at the NC3 domain of alpha 2(IX), we have synthesized undecapeptides containing the sequence around the glycosaminoglycan attachment site of the alpha 2(IX) chain. Antibody against the peptide, which was raised in rabbit, only recognized COLIX and made it possible to distinguish COLIX from PGIX. Evidence shows that this could be due to a difference in antigenicity of the NC3 domain of the alpha 2(IX) chain between COLIX and PGIX caused by the substitution of a chondroitin sulfate chain to the serine residue in this domain. Therefore, this antibody may be useful as a probe for studies on the functions of glycosaminoglycan substitution in type IX collagen.

Amino Acid Sequence↗

PubMed1992

Single pancreatic beta-cells from normal rats exhibit an initial decrease and subsequent increase in cytosolic free Ca2+ in response to glucose.

Since it was reported that glucose stimulation initially lowers as well as subsequently raises the cytosolic free calcium concentration [( Ca2+]i) in pancreatic islet cells from hyperglycemic ob/ob mice, it has been argued whether the lowering of [Ca2+]i is physiological or artifactual. In the present study, [Ca2+]i in single pancreatic beta-cells from normal rats was measured by Fura-2 microfluorometry. Following elevation of the glucose concentration from 2.8 mM (basal) to 16.7 mM, a bimodal change in [Ca2+]i, an initial decrease and subsequent increase, was demonstrated. When the basal glucose concentration was raised to 5.6 mM, the stimulation with 16.7 mM glucose also induced the decrease in [Ca2+]i in the majority of the cells, though the amplitude of the decrease was reduced. An elevation of the glucose concentration from 2.8 to 5.6 mM induced the decrease in [Ca2+]i but not usually the increase in [Ca2+]i. Removal of extracellular Ca2+ eliminated the increase in [Ca2+]i without affecting the decrease in [Ca2+]i. Thus, the decrease and increase in [Ca2+]i were clearly dissociated under certain conditions. In contrast, mannoheptulose (an inhibitor of glucose metabolism) inhibited both the decrease and increase in [Ca2+]i. These results demonstrate that the glucose-induced bimodal change in [Ca2+]i is a physiological response of islet beta-cells, and that the decrease and increase in [Ca2+]i are generated by mutually-independent mechanisms which are operated through glucose metabolism by islet beta-cells.

Animals↗

PubMed1992

Atrial contractility affects phasic blood flow velocity of atrial small vessels in the dog.

OBJECTIVES: The aim was to evaluate the relative contribution of atrial muscle contraction and atrial pressure to the phasic patterns of left atrial arterial and venous flows. METHODS: Using a laser Doppler velocimeter, blood velocities were measured in the atrial small arteries and veins (outer diameter: 150-500 microns) in anaesthetised open chest dogs (n = 21). The velocity sensor was fixed on the vessel surface with a drop of cyanoacrylate glue when good quality Doppler signals were consistently observed. Left atrial pressure and the contractility of the left atrium were changed by premature ventricular contraction and by intracoronary injection of isoprenaline (0.5 microgram), respectively. RESULTS: Premature ventricular contraction increased left atrial pressure significantly during arterial velocity measurements from 8.1(SD 2.7) to 16.4(1.3) mm Hg and during venous measurements from 8.2(1.2) to 14.3(3.7) mm Hg. However, premature ventricular contraction did not change the blood velocity patterns, the maximum deceleration rate of the systolic velocity wave in arteries, or the maximum acceleration rate of the systolic velocity wave in veins. Although isoprenaline did not change the left atrial pressure, it decreased minimum arterial blood velocity during atrial systole, from 3.3(3.4) to -2.5(3.2) cm.s-1, and increased maximum venous blood velocity from 15.9(5.5) to 19.2(7.4) cm.s-1. Isoprenaline also increased both the maximum arterial systolic velocity deceleration rate, from 90(45) to 234(143) cm.s-2, and the maximum venous systolic velocity acceleration rate from 356(230) to 763(366) cm.s-2. CONCLUSIONS: (1) Left atrial pressure is not a major determinant of the blood flow patterns of the atrial arteries and veins, and therefore it may not closely reflect pressure around mural vessels. (2) Atrial contractility affects the blood flow patterns of the atrial arteries and veins.

Animals↗

PubMed1992

Blood velocity patterns in poststenotic regions and velocity waveforms for myocardial inflow associated with coronary artery stenosis in dogs.

Velocity profiles across a vessel were investigated in poststenotic regions of the canine left coronary artery by our 80-channel 20 MHz ultrasound velocimeter. The velocity waveform in a small artery just before its penetration into myocardium was measured by our laser Doppler method. The poststenotic velocity configuration was characterized by a narrow region of high velocity with diastolic reverse flow near the wall which may dissipate energy. The velocity waveform in the distal small arteries exhibited increased systolic reverse flow with decreased diastolic forward flow, resulting in a remarkable reduction of coronary inflow into the myocardium.

Animals↗

PubMed1992

Phasic characteristics of arterial inflow and venous outflow of right ventricular myocardium in dogs.

To clarify the characteristics and causes of phasic blood flow in coronary circulation of the right ventricle we measured blood velocities in peripheral portions of the right coronary artery and vein in dogs under three conditions: control, transient pulmonary stenosis, and isoproterenol administration. An optical fiber sensor of a laser Doppler velocimeter was fixed onto the vessels (150-500 microns OD) with cyanoacrylate. The phasic pattern of distal arterial velocity was compared with the proximal velocity in the right coronary artery measured with an ultrasound pulsed Doppler velocimeter. Systolic-to-total velocity area ratio in the small epicardial artery [0.38 +/- 0.03 (SE)] was found to be smaller than in the large epicardial artery (0.51 +/- 0.02, P less than 0.01), indicating a capacitive filling of the epicardial artery during systole. The velocity waveform in small right coronary veins was predominantly systolic; i.e., it increased with a rise of right ventricular pressure and decreased with right ventricular relaxation. Comparison of the waveforms during isoproterenol infusion and pulmonary stenosis indicates that contraction of the ventricle is more important than right ventricular systolic pressure in retarding arterial inflow and accelerating venous outflow.

Animals↗

PubMed1992

Effect of coronary stenosis on phasic pattern of septal artery in dogs.

To analyze the effect of coronary stenosis on the phasic pattern of blood flow velocity into the myocardium, we measured septal artery blood velocities under control conditions, i.e., no stenosis (N), with moderate (S1) and severe (S2) proximal coronary arterial stenosis, and during complete occlusion. In eight anesthetized open-chest dogs, the blood velocity measurements were performed using our 20-MHz multichannel pulsed Doppler method before and after intracoronary adenosine administration. Under N, the coronary perfusion pressure was set to approximately 100 mmHg, with S1 the poststenotic pressure was approximately 60 mmHg, and with S2 it was decreased to 35 mmHg. Septal arterial blood velocity area, which is the time-integrated envelope of the velocity, was divided into three components; systolic retrograde velocity area, systolic anterograde velocity area, and diastolic anterograde velocity area. There were no significant changes from N to S1 in any of the three velocity areas, which is a measure of the flow. Total inflow decreased from N to S2 by 52% (P less than 0.05). Diastolic anterograde flow decreased from N to S2 by 32% (P less than 0.05). Systolic retrograde flow increased from N to S2 by 75% (P less than 0.05). Systolic anterograde flow was almost unchanged by increasing stenosis. After complete occlusion, the septal artery exhibited a to-and-fro flow pattern. Adenosine-induced vasodilation reduced poststenotic pressure (P less than 0.05) and enhanced systolic retrograde flow without a significant increase in diastolic anterograde flow. Systolic retrograde flow increased at S1 by 49% (P less than 0.05) and at S2 by 27% (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗

PubMed1992

Pituitary adenylate cyclase activating polypeptide and vasoactive intestinal peptide increase cytosolic free calcium concentration in cultured rat hippocampal neurons.

Recently, pituitary adenylate cyclase activating polypeptide (PACAP) was isolated from ovine hypothalamus and it was shown to stimulate adenylate cyclase in rat pituitary cells, neurons, and astrocytes. PACAP exhibits a 68% amino acid sequence homology with vasoactive intestinal peptide (VIP); however, it is 1000 times more potent than VIP in stimulating adenylate cyclase. In view of the wide distribution of PACAP and its receptor in the central nervous system, PACAP is likely to act as a neurotransmitter or neuromodulator as well. In the present study, we investigated the effects of PACAP38 on cytosolic-free calcium concentrations ([Ca2+]i) and compared these effects with those of VIP in cultured rat hippocampal neurons. Calcium concentrations, at the single cell level, were measured using fura-2, a calcium sensitive fluorescent dye, and fura-2-loaded neurons were continuously superfused at 37 C and viewed under an inverted microscope. Images of these neurons were recorded at 10-sec intervals by a video camera equipped with an Argus-50/CA system which controls the image acquisition and display. [Ca2+]i was quantitated from the intensities of fluorescence of the cells at two excitation wavelengths of 340 and 380 nm. The ratio of the intensities of emitted fluorescence (340/380 nm) was calibrated to determine [Ca2+]i. PACAP38 (0.1 nM) increased [Ca2+]i in some hippocampal neurons. As the concentration of peptide was increased from 0.1 to 10 nM, the accumulated number of hippocampal neurons responding to PACAP38 progressively increased and reached a plateau at 10 nM. Total neurons (33.0 +/- 5.3%, n = 4; 502 neurons) were found to respond to 100 nM PACAP38. The half-maximal concentration (ED50) of PACAP38 was 2.60 +/- 0.77 nM. Typically, 60-90 sec after the addition of PACAP38 (10 nM), [Ca2+]i increased from basal levels of 50-100 to 150-300 nM. VIP also increased [Ca2+]i, but required 1 microM or higher concentration for a considerable number of cells to respond. The number of hippocampal neurons responding to VIP at 1 microM was 28.9 +/- 9.8% (n = 4; 442 cells) which was comparable to the population of neurons responding to 10 nM PACAP38. The ED50 for VIP was 0.68 +/- 0.38 microM which was approximately 260 times higher than the ED50 for PACAP38. Neither 1-10 microM nitrendipine, a L-type voltage-dependent Ca2+ channel blocker, or 1 microM omega-conotoxin GVIA, a N-type voltage-dependent Ca2+ channel blocker, altered the PACAP-induced Ca2+ increment. Removal of Ca2+ from the superfusion media did not influence the PACAP38-induced increase of [Ca2+]i.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

L-argininosuccinate modulates L-glutamate response in acutely isolated cerebellar neurons of immature rat.

Fura-2 microfluorometry revealed that as little as 10(-13) M L-argininosuccinate, an intermediate of the L-arginine synthesizing pathway, is sufficient to reduce the increase in intracellular free calcium produced by L-glutamate in the acutely isolated cerebellar neurons of immature rats. In these neurons L-argininosuccinate also reduced the response to quisqualate, but not the response to kainate or N-methyl-D-aspartate. The results suggest that L-argininosuccinate may function as a transmitter or modulator in the brain.

Animals↗

PubMed1991

Seasonal changes in seawater adaptability and plasma levels of prolactin and growth hormone in landlocked sockeye salmon (Oncorhynchus nerka) and amago salmon (O. rhodurus).

In order to clarify the roles of prolactin (PRL) and growth hormone (GH) in the development of seawater adaptability in salmonids, seasonal changes in salinity tolerance, plasma PRL, and plasma GH were examined in juvenile landlocked sockeye salmon (Oncorhynchus nerka) and amago salmon (O. rhodurus). Assessed by the 24-hr seawater-challenge test, the landlocked sockeye salmon possessed seawater adaptability as underyearlings in spring, which was maintained throughout the year, and a further increase was observed as yearlings the next spring. An increase in seawater adaptability was observed in silvery juvenile amago salmon as underyearlings from autumn to winter, when some of the wild population migrate to the sea. Precociously mature amago salmon, which did not develop a silvery body color but maintained distinct parr marks, also showed an improvement in seawater adaptability during autumn to winter, although plasma sodium levels after transfer to seawater were still higher than those of the silvery juveniles. In both sockeye and amago salmon, seasonal changes in plasma levels of PRL and GH were not correlated with development of seawater adaptability. In both species, acclimation to seawater resulted in decreased plasma levels of PRL irrespective of their adaptability to seawater, in agreement with the inhibitory effects of PRL in seawater adaptation. On the other hand, plasma GH levels increased only when seawater adaptability was high, in agreement with previous observations indicating an important role of GH in seawater adaptation of salmonids.

Adaptation, Physiological↗

PubMed1991

Effect of left ventricular hypertrophy secondary to systemic hypertension on left coronary artery flow dynamics.

STUDY OBJECTIVE: The aim was to clarify the characteristics of the phasic blood velocity pattern and their possible causes in left ventricular hypertrophy secondary to systemic hypertension. DESIGN: Measurements of blood velocities in the left anterior descending coronary artery were made with a 20 MHz Doppler catheter with a top mounted annular crystal. All patients had normal coronary arteriograms. PATIENTS: 23 hypertensive patients [systolic/diastolic pressure: 181(SD 15)/100(4) mm Hg)] with left ventricular hypertrophy, and 13 atypical chest pain patients without left ventricular hypertrophy or any abnormal haemodynamic findings (normal controls) entered the study. MEASUREMENTS AND MAIN RESULTS: The left anterior descending coronary artery blood velocity waveform in pressure overloaded left ventricular hypertrophy was characterised by delayed early diastolic inflow. The diastolic rise time of coronary flow (TDR), ie, the time from the beginning of diastole to peak velocity, was higher in patients with hypertensive left ventricular hypertrophy than in normal controls, at 145(56) v 66(15) ms, p less than 0.001. In patients with hypertensive left ventricular hypertrophy, TDR correlated well with the degree of hypertrophy (r = 0.83, p less than 0.01) and also with peak left ventricular systolic pressure (r = 0.62, p less than 0.01). The coronary flow reserve, calculated from the ratio of the diastolic mean velocity after intracoronary injection of papaverine to the resting flow velocity, decreased with prolongation of TDR (r = 0.58, p less than 0.02). CONCLUSIONS: (1) Impairment of early diastolic coronary arterial inflow is the most remarkable characteristic in pressure overloaded left ventricular hypertrophy; (2) preceding systolic vascular compression and impaired left ventricular relaxation correlate with the delayed early diastolic inflow; (3) the delayed inflow is an important possible cause of the decreased coronary flow reserve in the hypertensive left ventricular hypertrophy.

Adult↗

PubMed1991

[A case of Pasteurella multocida subsp. multocida complicated with diabetes mellitus].

We report a case of sepsis who died caused by Pasteurella multocida subsp. multocide sepsis. A 68-year-old male was admitted to Azusawa Hospital because of disturbance of consciousness. He had been suffering from diabetes mellitus combined with gangrene, but received no treatment. The patient died 24 h after hospitalization, and Pasteurella multocida subsp. multocida was isolated from his blood. Laboratory tests showed that CRP; 5+ WBC; 15,400/microliters, TP; 5.2 g/dl. Although Pasteurella multicida subsp. multocida seemed to cause mild infection in healthy subjects, it can cause severe systemic illnesses such as sepsis and meningitis in compromised hosts. It should be considered that the contact with pets will increase the incidence of systemic severe infection with this agents.

Aged↗

PubMed1991

Growth hormone and prolactin gene expression and release in the pituitary of rainbow trout in serum-free culture.

The trout pituitary continuously released a large amount of GH for over a week in serum-free culture, but PRL secretion declined by day 2 in culture. The total amount of GH released during the 8 days exceeded the initial content. The pituitary content of PRL remained unchanged after 8 days of culture. The number of weakly stained GH-immunoreactive (ir) cells was increased by day 4 in culture. The GH mRNA levels in individual cells as revealed by in situ hybridization were maintained at around the same level throughout culture. In contrast, the stainability of PRL-ir cells remained unchanged during culture, although the levels of PRL mRNA decreased by day 8. Electron microscopic immunocytochemistry showed a decrease in the numbers of secretory granules and dilation of rough endoplasmic reticulum in GH-ir cells. GH synthesis, measured by incorporated [3H]leucine after GH immunoprecipitation, was elevated 120% on day 8 over day 0. The dominant control of GH and PRL secretion in rainbow trout seems to be the converse of those seen in mammals; inhibition for GH and stimulation for PRL.

Animals↗

PubMed1991

[Left ventricular hypertrophy secondary to systemic hypertension: its effect on coronary hemodynamics].

To clarify the characteristics and possible causes of phasic blood velocity patterns in pressure overload hypertrophy, we measured blood flow velocities in the left anterior descending coronary arteries in 16 patients with left ventricular hypertrophy secondary to systemic hypertension. These measurements were made with a 20MHz Doppler catheter. All patients had normal coronary arteriograms. The blood flow velocity patterns were characterized by the decrease in the rise of early diastolic inflow velocity. Prolongation in the time from the onset of diastole to peak velocity (TDPV) correlated with the degree of left ventricular hypertrophy. TDPV was prolonged in proportion to the increase in the peak left ventricular systolic pressure and left ventricular ejection fraction. The flow reserve calculated from the ratio of the diastolic mean velocity after the intracoronary injection of papaverine to the resting flow showed a trend toward the decrease proportional to the prolongation in TDPV due to an increase of wall thickness. In conclusion, preceding systolic vascular compression and systolic vascular strain can be factors causing early diastolic inflow disturbance in left ventricular hypertrophy secondary to hypertension. The decrease of coronary reserve may partially be attributable to the decrease in the rise of early diastolic inflow velocity.

Adult↗

PubMed1991

[Treadmill exercise test in patients with hypertrophic cardiomyopathy with and without coronary artery disease].

We studied whether the treadmill exercise test can discriminate between normal and significant narrowing of coronary arteries in patients with hypertrophic cardiomyopathy (HCM) accompanied with chest pain, and we compared the extent of myocardial ischemia during exercise. Thirty one patients with HCM were divided into two groups; 21 with normal coronary arteries and 11 with significant narrowing of coronary arteries. The treadmill exercise test was carried out in both groups. The following parameters were more frequently seen in the group with coronary stenosis. (1) short treadmill time (338, sec vs 542, p less than 0.05). (2) delta SBP less than or equal to 60 mmHg (delta: end point minus rest, 10 cases vs 12, 0.05 less than p less than 0.1). (3) significant delta ST depression (0.17 mV vs 0.05, p less than 0.05). (4) large delta ST/delta HR (3.3 microV.min/beats vs 0.7). delta ST/delta HR greater than or equal to 2.0 was the most useful for differentiating the two groups, and it was 90% in index both sensitivity and specificity for diagnosis of HCM with significant narrowing of the coronary arteries. It was concluded that treadmill exercise induced more severe myocardial ischemia in patients with HCM who had significant narrowing of the coronary arteries than in patients with HCM who had angiographically normal coronary arteries. The delta ST/delta HR was the most useful index for diagnosis of HCM with significant narrowing of the coronary arteries.

Blood Pressure↗

PubMed1990

Occurrence in chick embryo vitreous humor of a type IX collagen proteoglycan with an extraordinarily large chondroitin sulfate chain and short alpha 1 polypeptide.

We have prepared a high buoyant density proteoglycan fraction from the vitreous humor of 13-day-old chick embryos. Using immunoblot analysis coupled with chondroitinase digestion, we demonstrate that the purified preparation is composed predominantly of type IX collagen-like chondroitin sulfate proteoglycan with an alpha 1(IX) chain Mr approximately 23,000 shorter than the known alpha 1 in cartilage type IX. Also different from cartilage type IX is the size of the chondroitin sulfate chain attached to the alpha 2(IX) polypeptide; its Mr is approximately 350,000 indicating that it is approximately 10 times larger in vitreous humor than in cartilage. Examination of vitreous bodies at different developmental stages indicates that a transition occurs in the size of alpha 1(IX) in a well defined temporal pattern; at about stage 31, a cartilage-type alpha 1(IX) of Mr 84,000 is the predominant species, whereas at stage 36 and thereafter, a Mr 61,000 species appears with a concomitant disappearance of the Mr 84,000 species. Immunostaining for type IX collagen followed by electron microscopic observation of 13-day-old chick embryo vitreous humor reveals a regular D-periodic arrangement of vitreous type IX collagen proteoglycan along thin fibrils. It seems possible that the chondroitin sulfate chains of extraordinarily high viscosity and high molecular weight may extend away from the fibrils, thus contributing to structural as well as functional properties of this unique matrix.

Aggrecans↗

PubMed1990

Radionuclide assessment of left ventricular function during dobutamine infusion in patients with coronary artery disease: comparison with ergometer exercise.

The effects of dobutamine on left ventricular function were assessed employing radionuclide ventriculography (RNV) in 7 normal subjects (Group 1) and 21 patients with coronary artery disease (Group 2). After routine bicycle ergometer exercise RNV, dobutamine infusion was started at 5 micrograms/kg/min and the dosage was increased by 5 micrograms/kg/min every 4 minutes to a total of 15 micrograms/kg/min. In Group 1, left ventricular ejection fraction (LVEF) increased by both ergometer exercise and dobutamine infusion. In Group 2, LVEF did not increase during exercise, but increased during dobutamine infusion without evidence of significant myocardial ischemia. Only 2 patients in Group 2 had new regional wall motion abnormality. Left ventricular end-diastolic volume (LVEDV) in Group 2 increased from 191 +/- 19 to 210 +/- 18 ml during ergometer exercise, but decreased from 193 +/- 18 to 153 +/- 19 ml during dobutamine infusion. Short-term low-dose infusion of dobutamine may be used in patients without evidence of significant myocardial ischemia, but probably cannot be substituted for exercise testing in patients with mild to moderate coronary artery disease.

Coronary Disease↗