Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Certified Reference Material for Analytical Quality Assurance of Minor and Trace Elements in Food and Related Matrixes Based on a Typical Japanese Diet: Interlaboratory Study

A Certified Reference Material (CRM) was prepared at the National Institute for Environmental Studies (NIES), Japan, in collaboration with the National Institute of Radiological Sciences (NIRS), Japan, for the analytical quality assurance of minor and trace elements in food and related matrixes. The starting material for the CRM was all food served in 29 households in Japan over two 3-day periods in 1997–1998, and thus the CRM represented a typical Japanese diet. All foods (meals, snacks, and beverages) were homogenized, freeze-dried, pulverized, blended, dispensed into 1100 bottles, and sterilized. The within- and between-bottle homogeneity of the prepared CRM was satisfactory for most of the elements. The concentrations of 14 elements (Na, Mg, K, Ca, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Ba, and U) were certified based on a collaborative analysis involving NIES, NIRS, and 20 other laboratories. Reference values were given for the concentrations of 12 additional elements (P, Cl, Fe, Co, Ni, Br, Rb, Mo, I, Cs, Pb, and Th). The elements certified and those given reference values include minerals, essential trace elements, contaminant elements, and long-lived radionuclides. Thus, this CRM is of practical value in the quality assurance of element analysis of foods and diets in nutritional, environmental, and radiological research.

The prevalence of autoimmune disease in patients with esophageal achalasia

Achalasia is a rare disease of the esophagus that has an unknown etiology. Genetic, infectious, and autoimmune mechanisms have each been proposed. Autoimmune diseases often occur in association with one another, either within a single individual or in a family. There have been separate case reports of patients with both achalasia and one or more autoimmune diseases, but no study has yet determined the prevalence of autoimmune diseases in the achalasia population. This paper aims to compare the prevalence of autoimmune disease in patients with esophageal achalasia to the general population. We retrospectively reviewed the charts of 193 achalasia patients who received treatment at Toronto's University Health Network between January 2000 and May 2010 to identify other autoimmune diseases and a number of control conditions. We determined the general population prevalence of autoimmune diseases from published epidemiological studies. The achalasia sample was, on average, 10-15 years older and had slightly more men than the control populations. Compared to the general population, patients with achalasia were 5.4 times more likely to have type I diabetes mellitus (95% confidence interval [CI] 1.5-19), 8.5 times as likely to have hypothyroidism (95% CI 5.0-14), 37 times as likely to have Sjögren's syndrome (95% CI 1.9-205), 43 times as likely to have systemic lupus erythematosus (95% CI 12-154), and 259 times as likely to have uveitis (95% CI 13-1438). Overall, patients with achalasia were 3.6 times more likely to suffer from any autoimmune condition (95% CI 2.5-5.3). Our findings are consistent with the impression that achalasia's etiology has an autoimmune component. Further research is needed to more conclusively define achalasia as an autoimmune disease.

Effect of angiotensin-converting enzyme inhibitor (enalapril or imidapril) on ventilation during exercise in patients with chronic heart failure secondary to idiopathic dilated cardiomyopathy

Eighteen patients with heart failure were studied to clarify whether angiotensin-converting enzyme inhibitor treatment improves excess ventilation during exercise. Treatment with angiotensin-converting enzyme inhibitors had a beneficial effect on excess ventilation during exercise, without significant improvement in exercise capacity in patients with moderate congestive heart failure.

Prodrugs for systemic bioreductive activation-independent delivery of phyllohydroquinone, an active form of phylloquinone (vitamin K1). 1: Preparation and in vitro evaluation

With the aim of overcoming the delivery problems (water-solubility and bioreductive activation problems) of phyllohydroquinone (PKH), an active form of phylloquinone (PK, vitamin K1), the N,N-dimethylglycine esters of phyllohydroquinone (1-mono, 1; 4-mono, 2; and 1,4-bis, 3) have been synthesized and assessed in vitro as a prodrug for the systemic bioreductive activation-independent delivery of PKH. The hydrochloride salts of the esters were found to be quite soluble in water. Hydrolysis of the esters in rat liver S9 fraction, rat plasma and phosphate buffer, pH 7.4, at 37 degrees C, was kinetically studied in the presence and absence of an esterase inhibitor. The hydrolysis was catalyzed by esterases located in rat liver and rat plasma and quantitatively yielded PKH. The enzymatic cleavage and the vitamin K-dependent carboxylation activity of the esters in the rat liver microsome preparation at pH 7.2 and 25 degrees C were studied. The regeneration of PKH from the esters was catalyzed by carboxylesterases located in the rat liver microsome, and the order was as follows: 1 > 3 > 2. The carboxylation was stimulated by selected ester 1 in the absence of dithiothreitol, an activator of the vitamin K cycle. The carboxylation activity of 1 was strongly inhibited in the presence of eserine, a carboxylesterase inhibitor. Compound 1 could also stimulate carboxylase under warfarin-poisoning conditions, where the vitamin K cycle was strongly inhibited. These results indicated that these highly water-soluble and liver-esterase hydrolyzable ester derivatives of PKH are potential candidates for parenteral prodrugs which can thus achieve the systemic bioreductive activation-independent delivery of PKH.

Tumor scintigraphy by the method for subtracting the initial image with technetium-99m labeled antibody

The method for subtracting the initial image from the localization image was evaluated for radioimmunoscintigraphy of tumors with technetium-99m (Tc-99m) labeled antibodies. Monoclonal antibodies were parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, both of which have been found to discriminate CEA in tumor tissues from the CEA-related antigens. After reduction of the intrinsic disulfide bonds, these antibodies were labeled with Tc-99m. In vivo studies were performed on athymic nude mice bearing the human CEA-producing gastric carcinoma xenografts. Though biodistribution results showed selective and progressive accumulation of Tc-99m labeled antibodies at the tumor site, high radioactivity in blood was inappropriate for scintigraphic visualization of the tumors within a few hours. We examined the subtraction of the initial Tc-99m image from the Tc-99m localization image after a few hours. Subtracted images of the same count reflected the in vivo behavior of the Tc-99m radioactivity. The subtracted scintigrams revealed excellent tumor images with no significant extrarenal background. Visualization of the tumor site was dependent on antigen-specific binding and nonspecific exudation. These results demonstrate that a method of subtraction of the initial image may serve as a potentially useful diagnostic method for an abnormal site for agents with a low pharmacokinetic value.

Effects of a water-soluble prodrug of vitamin E on doxorubicin-induced toxicity in mice

Effects of the administration of a water-soluble prodrug of vitamin E on doxorubicine (DXR)-induced lethal and oxidative toxicity in mice were studied. The prodrug used was d-alpha-tocopheryl N,N-dimethylaminoacetate hydrochloride (TDMA). It was intravenously administered to animals 2 h prior to an intraperitoneal administration of DXR (15 mg/kg). The single preadministration of the prodrug (10-50 mg/kg equivalent for d-alpha-tocopherol) delayed the DXR-induced death and the ameliorative effect was TDMA-dose dependent. The extent of total lipid peroxidation of the heart and liver was assessed by 2-thiobarbituric acid reactant substance levels. DXR significantly accelerated lipid peroxidation in the liver but not in the heart. The elevation of liver lipid peroxide was significantly suppressed to a normal range by a single preadministration of TDMA (50 mg/kg equivalent for d-alpha-tocopherol). TDMA did not significantly affect the antitumor activity of DXR in mice inoculated with L1210 leukemia cells.

Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy

OBJECTIVE

To determine whether dobutamine stress echocardiography can predict the improvement of left ventricular systolic function in patients with dilated cardiomyopathy (DCM).

METHODS

Myocardial contractile reserve, as assessed by dobutamine stress echocardiography, was determined in 18 patients with DCM (mean (SD) age 53 (13) years, left ventricular ejection fraction (LVEF) 28 (10)%) and compared with changes in LVEF during a follow up period of 15 (8) months. The LVEF and regional left ventricular wall motion score (0, normal to 4, dyskinesis) of 12 segments in short axis and four chamber views were analysed before and after dobutamine infusion (5-20 microg/kg/min).

RESULTS

During a follow up period of 15 (8) months, a significant improvement in LVEF (> 20%) was found in seven patients but not in the remaining 11. Baseline haemodynamic findings were similar in both groups. Patients with an improvement in follow up LVEF showed a greater change in wall motion score from baseline during dobutamine infusion than patients with no improvement (at rest, 1.7 (0.4) v 1.9 (0.2), NS; dobutamine 10 microg/kg/min, 0.6 (0.4) v 1.2 (0.4), p < 0.05). The percentage change in LVEF during dobutamine infusion was also significantly greater in patients who showed improvement than in those who did not. The change in LVEF during the follow up period (follow up LVEF/baseline LVEF) correlated well with the change in LVEF during dobutamine stress (LVEF at rest/LVEF at dobutamine 10 microg/kg/min; r = 0.74, p < 0.001).

CONCLUSIONS

Changes in left ventricular systolic performance during low dose dobutamine stress echocardiography are a useful marker to predict the outcome of left ventricular systolic function in patients with DCM.

Technetium-99m complex of N-(2-pyridylmethyl)iminodiacetic acid as a new renal radiopharmaceutical

A tetradentate chelating agent constituting of an iminodiacetic acid group and a nitrogen atom of pyridine, N-(2-pyridylmethyl)iminodiacetic acid (PMIDA), was coordinated with 99mTc and evaluated as a renal functional agent. The complex of PMIDA with 99mTc was prepared by using a stannous chloride solution as a reducing agent. The chelating efficiency was analyzed by thin layer chromatography and electrophoresis. Chelation with 99mTc resulted in a single radiochemical product. Biological studies were performed in mice and rats. 99mTc-PMIDA was removed from the circulation solely by the kidneys. Clearance of 99mTc-PMIDA from the blood and the kidneys was as rapid as that of 99mTc-diethylenetriaminepentaacetic acid. The rate of blood clearance was unaffected by the administration of probenecid (a test for tubular secretion by the weak-acid mechanism), so that the glomerular filtration rate could be estimated by measuring its clearance from the blood. The results in animals with myohemoglobinuric acute renal failure suggested that 99mTc-PMIDA might be a useful renal function radiopharmaceutical.

Technetium-99m complexes with steroid-2-aminooxyethyliminodiacetic acid conjugates

Conjugates of 2-aminooxyethyliminodiacetic acid with estrone, testosterone, epiandrosterone, 17-alpha-hydroxy-progesterone and progesterone were synthesized and their complexes with Tc-99m were successfully prepared in good yields, which indicated the agent to be promising for metal-labeling of biomolecules and related substances containing one or more carbonyl groups. The biodistribution and scintigraphic studies in mice bearing Ehrlich tumor and mammary tumor showed that the radioactivity accumulated considerably in the tumor tissues, but the tumor images were somewhat obscured.

Prodrug for bioreductive activation-independent delivery of menahydroquinone-4: human liver enzymatic activation and its action in warfarin-poisoned human liver

The N,N-dimethylglycine esters of menahydroquinone-4 (1-mono, 1; 4-mono, 2; 1,4-bis, 3) were established in previous reports as prodrugs that could achieve the systemic bioreductive activation-independent delivery of menahydroquinone-4 (MKH), the active form of menaquinone-4 (MK-4), in rat. The present study was undertaken to investigate if the prodrugs could undergo cleavage to parent drug (MKH) by a human tissues enzyme catalyzed hydrolytic pathway, the mechanism of the prodrugs for vitamin K-dependent carboxylation in human liver and their action in the warfarin poisoned human liver. The hydrolysis of the esters was shown to be catalyzed by esterases located in human liver but not in human plasma. The susceptibility of the esters to undergo human liver esterase hydrolysis was affected by the esterified position: 1>2>3. By using a human liver microsomal test system, the stimulation of vitamin K-dependent carboxylation with the prodrugs was determined. The prodrug could stimulate the carboxylation activity in the absence of dithiothreitol, an artificial activator of the reductive activation pathway of MK-4. The carboxylation activity of the prodrug was strongly inhibited in the presence of eserine, an esterase inhibitor. The prodrug could also stimulate the carboxylase under warfarin-poisoned conditions, where the vitamin K cycle was strongly inhibited. The results confirmed that the prodrug could generate MKH in human liver (active site), and that the resultant MKH could act as a cofactor for the carboxylase without reductive activation processes of MK-4 to MKH. Such bioreductive activation-independent vitamin K-dependent carboxylation characteristic of the prodrug leads to enhanced pharmacological efficacy in the treatment of hypoprothrombinaemia induced in patients with coumarin and cephalosporin therapies.

[Congenital aortic regurgitation complicated by infective endocarditis of tricuspid valve due to spontaneous closure of ventricular septal defect: a case report]

A 32-year-old woman presented with a rare case of tricuspid valve endocarditis causing inflammatory reopening of the spontaneously closed ventricular septal defect (VSD), associated with aortic valve malformation. She was admitted to our hospital because of fever lasting 4 weeks. Severe aortic regurgitation was revealed by color Doppler echocardiography. Blood culture identified Microccus faecalis. Antibiotics were administered over 3 weeks, but serial echocardiography showed a developing vegetation in the right ventricle and left-to-right shunt flow. The diagnosis was infective endocarditis complicated by aortic ring abscess and interventricular septal fistula. Surgery performed on the 22nd hospitalized day found a vegetation of the tricuspid valve, a membranous type of VSD, and aortic valve malformation. Aortic valve replacement, patch closure of VSD, and tricuspid valvuloplasty achieved a successful outcome.

Diagnostic approach in exercise testing to detect a significant narrowing of the left anterior descending coronary artery in inferior vs posterior myocardial infarction

To detect a significant narrowing of the left anterior descending artery in patients with inferior/posterior myocardial infarction, 200 patients underwent standard exercise testing. Age, gender, and grade of stenosis of the left anterior descending artery were similar in 138 patients with inferior myocardial infarction and 62 with posterior myocardial infarction. In patients with left anterior descending artery stenosis, there were more lateral leads with ST-segment depression (1.8+/-1.0 vs 1.1+/-1.1; p<0.01) and fewer anterior leads with ST-segment depression (2.1+/-1.4 vs 2.9+/-1.4; p=0.02) in those with inferior myocardial infarction than in those with posterior myocardial infarction. Applying the criterion of exercise-induced ST-segment depression > or = 0.1 mV, sensitivities and specificities in detecting left anterior descending artery stenosis were 98% and 21% respectively in inferior myocardial infarction and 94% and 26% respectively in posterior myocardial infarction. In contrast, discriminant analysis revealed sensitivities and specificities of 77% and 91% respectively in inferior myocardial infarction and 71% and 81% respectively in posterior myocardial infarction using the variables related to severity of inducible ischemia and lateral and anterior lead ST-segment depression. These results indicate that a multivariate approach underscoring the site of myocardial infarction can help in identifying stenosis of the left anterior descending artery in patients with inferior/posterior myocardial infarction.

Adult T cell leukemia/lymphoma with massive involvement of cardiac muscle and valves

An autopsy case of a 58-year-old woman with massive cardiac involvement of adult T cell leukemia/lymphoma (ATLL) is reported. She developed cardiac failure due to aortic and mitral regurgitation with cardiac infiltration of ATLL cells, and underwent replacement of both aortic and mitral valves. Studies of the cut-surfaces revealed diffuse thickening of the subendocardial wall of the left chamber with widespread whitish-brown tumor infiltrates. In the regions surrounding the replaced aortic and mitral valves there was also massive tumor cell infiltration. The tumor cells infiltrating the cardiac muscle wall were T cell in origin and exhibited Leu-3a (CD4)-positive immunoreaction. Ultrastructurally, tumor cells contained markedly indented nuclei and some were attached directly to the muscle cells. These findings suggest that this was an unusual form of ATLL with widespread involvement of the heart.

Effect of diltiazem on sympathetic hyperactivity in patients with vasospastic angina as assessed by spectral analysis of arterial pressure and heart rate variability

The autonomic nervous system importantly regulates coronary arterial tone and vascular resistance. To evaluate a role of autonomic nervous activity and the effects of calcium antagonist in patients with vasospastic angina (VSA), 13 VSA patients with patent coronary arteries (58+/-8 years) and 8 normal subjects (58+/-12 years) were studied. Arterial pressure and electrocardiogram were continuously recorded with the patient in a supine position under controlled respiration (0.2 Hz). Low-frequency (LF) and high-frequency (HF) components of the beat-to-beat variabilities of systolic arterial pressure and RR interval were then estimated by autoregressive power spectral analysis. The LF power (normalized unit) of both systolic arterial pressure (0.53+/-0.17 vs 0.30+/-0.17, p < 0.01) and RR variabilities (0.51+/-0.20 vs 0.31+/-0.16, p < 0.05) in patients with VSA were greater than that in normal subjects. There was no significant difference in the HF power. Seven patients with VSA who were treated with diltiazem (60 to 200 mg/day) had normalized LF power (normalized unit) of both systolic arterial pressure (0.62+/-0.12 vs 0.33+/-0.16, p < 0.01) and RR variabilities (0.55+/-0.23 vs 0.36+/-0.14, p < 0.05), together with clinical improvement. An increased sympathetic vasomotor tone and cardiac sympathetic predominance may play an important role in patients with VSA. Diltiazem improves these sympathetic hyperactivities.

Clinical and electrocardiographic profiles producing exercise-induced U-wave inversion in patients with severe narrowing of the left anterior descending coronary artery

To elucidate which clinical features produce U-wave inversion, 339 patients with severe narrowing of the left anterior descending artery were evaluated. In patients with anterior myocardial infarction, extensive coronary artery disease and protected left anterior descending arterial territory are essential in the development of U-wave inversion, whereas electrocardiographic changes at rest in addition to anterior lead ST depression, rather than coronary anatomy, are important in those without anterior myocardial infarction.

[Usefulness of dipyridamole thallium scintigraphy in the diagnosis of coronary artery disease in elderly patients]

Patients suspected of having coronary artery disease (CAD) underwent dipyridamole thallium scintigraphy, exercise electrocardiography, and coronary angiography. Of the 500 patients studied, 163 were at least 65 years old, and 337 were less than 65 years old. Both CAD and multivessel CAD were more common in elderly than in younger patients (81% vs 69%, p < 0.01 for CAD; and 43% vs 26% p < 0.01 for multivessel CAD). In patients without myocardial infarction, the specificity of exercise electrocardiography was lower among elderly patients than among younger patients (52% vs 61%), but the sensitivity was higher (87% vs 75%). In contrast, both the sensitivity and the specificity of dipyridamole thallium scintigraphy were similar in the two age groups (86% vs 87% and 79% vs 74%). Among patients with myocardial infarction and a positive exercise test, reversible defects were equally common in the two age groups (60% vs 58%). The reversible defects were in areas remote from the area of infarction in half of the patients in both groups. Among patients with negative exercise-test results, reversible defects were more common in elderly patients than in younger patients (57% vs 38%). The reversible defects were in the infarcted area in 71% and 79% of these patients, respectively. These results indicate that dipyridamole thallium scintigraphy is a sensitive and specific method for detecting CAD, independent of age. It is particularly useful in identifying myocardial viability in the infarcted area.

Atherosclerotic aortic plaque detected by transesophageal echocardiography: its significance and limitation as a marker for coronary artery disease in the elderly

OBJECTIVES

To elucidate whether atherosclerotic aortic plaque detected by transesophageal echocardiography can be a clinically useful marker for coronary artery disease in the elderly.

BACKGROUND

Atherosclerotic aortic plaque detected by transesophageal echocardiography has been reported to be a marker for coronary artery disease. Its significance may be important particularly in the elderly population, although to our knowledge, there are no data yet available.

METHODS

We performed transesophageal echocardiography on 84 patients who had previously undergone coronary arteriography. The criteria used to diagnose atherosclerotic plaque on transesophageal echocardiography were the presence of focally or linearly increased echodensity of the aortic intima with lumen irregularity and thickening or ulceration.

RESULTS

Significant coronary artery disease (> or = 50% stenosis) was detected in at least one major coronary artery in 27 of the 84 patients. Aortic plaques were detected by transesophageal echocardiography in 25 of the 27 patients (93%) with coronary artery disease and in 30 of 57 patients (53%) without coronary disease (p<0.001). Among 24 patients 70 years or older, aortic plaques were present in 13 of 14 (93%) patients with coronary artery disease and 9 of 10 patients (90%) without coronary disease. Among 60 patients younger than 70 years, aortic plaques were present in 12 of 13 patients (92%) with coronary artery disease and 21 of 47 patients (45%) without coronary disease (p<0.01). The independent association between coronary artery disease and the presence of aortic plaque, age, gender, and other coronary risk factors was examined by multiple logistic regression analysis. In patients 70 years or older, the presence of aortic plaque failed to be a predictor of significant coronary artery disease, although it was indeed a strong predictor of coronary artery disease in patients younger than 70 years (p<0.05).

CONCLUSIONS

In elderly patients, atherosclerotic aortic plaque detected by transesophageal echocardiography is not useful in predicting significant coronary artery disease. It is useful only in a relatively younger population.

Delayed recovery of postexercise blood pressure in patients with chronic heart failure

Thirty-four patients with idiopathic dilated and ischemic cardiomyopathy underwent a symptom-limited cardiopulmonary exercise testing to evaluate the significance of postexercise blood pressure (BP) response. The postexercise BP response was useful in assessing the impaired exercise capacity and increased sympathetic activity in patients with heart failure.

Water-soluble prodrug of vitamin E for parenteral use and its effect on endotoxin-induced liver toxicity

The acid salts of aminoalkanecarboxylic acid esters of d-alpha-tocopherol were in a previous in vitro study identified as prodrug candidates for a parenteral form of d-alpha-tocopherol. The disposition of d-alpha-tocopheryl N,N-dimethylaminoacetate hydrochloride (TDMA), the most potential candidate for the prodrug, after a single intravenous administration was investigated and compared with that of the d-alpha-tocopheryl acetate (TA) and dl-alpha-tocopherol, solubilized with HCO-60, in order to establish the utility as a prodrug for i.v. administration. The preventive effect of the prodrug against endotoxin (lipopolysaccharide (LPS))-induced liver lipid peroxidation was also investigated in mice. The plasma and liver levels of alpha-tocopherol (Toc) were increased rapidly after i.v. administration of the prodrug. The distribution of Toc and TDMA in the plasma and the liver at 1 h was as follows; 2.1 +/- 0.2 (plasma, Toc), 2.0 +/- 0.2 (plasma, TDMA), 32.8 +/- 2.9 (liver, Toc), and 35.3 +/- 6.5% of dose (liver, TDMA). The rapid and liver-selective uptake and liver-esterase specific regeneration characteristics of the prodrug enhance the delivery of Toc to liver. The liver availability of Toc after i.v. administration of TDMA, TA and Toc were 116, 50 and 100%, respectively. The elevation of liver lipid peroxide induced with LPS was significantly suppressed to a normal range by a single i.v. postadministration of TDMA (over 10 mg/kg equivalent for Toc). These results indicated that the water-soluble and liver-esterase hydrolyzable derivative of Toc was a potential candidate for a parenteral prodrug which can thus achieve the systemic liver-specific delivery of Toc. Such effective and selective delivery of Toc into the liver can therefore lead to enhanced pharmacological efficacy against liver oxidative injury associated with free radicals.

Prognostic value of serum cholesterol level in Japanese patients with coronary artery disease

To determine the prognostic value of serum cholesterol level in Japanese patients with established coronary artery disease, we followed 330 consecutive patients with a left ventricular ejection fraction of > or = 50%. Over a period of 4.0 +/- 2.5 years, 53 patients (16%) experienced cardiac events. Multivariate analysis using Cox proportional hazard modeling revealed that obesity (risk ratio 4.3; p = 0.0001), the number of diseased vessels (risk ratio 1.9; p = 0.0001) and a serum cholesterol level > or = 220 mg/dl (risk ratio 2.3; p = 0.01) or > or = 200 mg/dl (risk ratio 2.1; p < 0.02) increase the risk of cardiac events. These results suggest that patients with established coronary artery disease and a serum cholesterol level > or = 200 mg/dl have a similar risk of experiencing a cardiac event as patients without left ventricular dysfunction and a serum cholesterol level > or = 220 mg/dl. Although the prevalence of coronary artery disease is low in Japan, the serum cholesterol level should be strictly controlled in subjects with established coronary artery disease to avoid future cardiac events.

Diagnostic significance of an exercise-induced prominent U wave in acute myocardial infarction

A prominent U wave induced by exercise testing in patients with anterior wall myocardial infarction is a highly specific but insensitive marker for the narrowing of the left circumflex or right coronary artery, although a U-wave increase alone with or without ST-segment depression may help better identify these coronary artery narrowings. In patients with inferior and/or posterior myocardial infarction, a prominent U wave is regarded as a simple electrocardiographic marker for inferior and/or posterior residual ischemia.

Radioimmunoscintigraphy using technetium-99m-labeled parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen in athymic nude mice bearing tumor

Biodistribution and imaging characteristics of Tc-99m-labeled parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, were evaluated in athymic nude mice bearing the human CEA-producing gastric carcinoma (MKN-45) xenografts. Group F monoclonal antibodies such as F11-39 and ChF11-39 have been found to recognize the protein epitopes present on the domain B3 of the CEA molecule and to discriminate CEA in tumor tissues from the CEA-related antigens. The Tc-99m labeling was performed by immediately mixing a reduced antibody by 2-mercaptoethanol with Tc-99m pertechnetate in the presence of stannous chloride. The labeling yields of the two antibodies were greater than 95% when estimated using gel chromatography. Although these Tc-99m-labeled antibodies were stable in neutral saline solution, Tc-99m from both labeled antibodies was associated with cysteine solution. Technetium-99m ChF11-39 was more susceptible to transchelation than was Tc-99m F11-39. The immunoreactivity of each Tc-99m-labeled antibody was confirmed using MKN-45 cell-binding assay. Biodistribution studies in tumor-bearing mice were performed at 1 h, 5 h, and 20 h after being given IV injections of 3.7 MBq of either Tc-99m F11-39 or Tc-99m ChF11-39. All tumor-to-organ uptake ratios increased with time for both Tc-99m-labeled antibodies. Imaging results also showed selective and progressive accumulation of both Tc-99m antibodies at the tumor site. Both these Tc-99m-labeled antibodies have proved to be good radiotracers giving satisfactory scintigrams of the CEA-producing tumor.

Tumor-specific accumulation of 125I-labeled mouse-human chimeric anti-CEA antibody in a xenografted human cancer model demonstrated by whole-body autoradiography and immunostaining

Whole-body autoradiography (WBAR) was used to study the biodistribution of 125I-labeled mouse-human chimeric antibody (Ch F11-39) to carcinoembryonic antigen (CEA) in athymic nude mice bearing the CEA-producing MKN-45 human gastric carcinoma xenografts. Significantly high uptake of 125I-Ch F11-39 in the tumors obtained by tissue-counting technique was confirmed by WBAR of mice of 12, 24, 48, and 96 h postinjection of 125I-Ch F11-39. When compared with histochemical or immunohistochemical staining results of the tumor tissue sections, imaging profiles of 125I-Ch F11-39 obtained by WBARs were topographically correlated with histopathological findings of tissues and immunohistochemical localization of CEA in the tumor tissues, indicating that the accumulation of 125I-Ch F11-39 at the tumor site is based on its specificity for CEA. These results demonstrate that this chimeric antibody may serve as a potential useful diagnostic and/or therapeutic reagent for human CEA-producing cancers.

In vitro properties and in vivo behavior of technetium-99m labeled fibrinogens

Fibrinogen was labeled with Tc-99m by two methods and in vitro stability and the in vivo behavior in mice were studied. The Tc-99m labeling was performed by mixing an unreduced fibrinogen (UnFib) or a reduced fibrinogen (ReFib) with Tc-99m pertechnetate in the presence of stannous chloride. In both of them, chelation with Tc-99m resulted in a single radiochemical product. For the in vitro stability studies, Tc-99m labeled fibrinogen (Tc-99m UnFib) was prepared with UnFib, and transchelation with cysteine solution was easy to produce compared to Tc-99m labeled fibrinogen (Tc-99m ReFib) prepared with ReFib. The radioactivity bound to clottable protein for Tc-99m UnFib and Tc-99m ReFib was about 70% and about 69%, respectively. The in vivo behavior of these labeled fibrinogens was studied, and their efficiencies for imaging an abscess and Ehrlich tumor in mice were determined with a gamma camera. Technetium-99m UnFib underwent a rapid partial exchange of the Tc-99m with compounds of the blood buffer system in vivo, resulting in early biologically active and would be incorporated into the abscess and tumor. The uptake in the abscess increased slightly over time with Tc-99m ReFib, but the abscess to blood and abscess to muscle ratios were 0.09 and 2.6 at 5 hr, respectively. Clearly delineated images of abscess were obtained beginning at about 5 hr after injection. The tumor to blood and tumor to muscle ratios were 0.05 and 1.4 at 5 hr, respectively. The Ehrlich tumor image in mice was slightly visible at 10 hr. The short half-life of Tc-99m was inappropriate for fibrinogen with a low pharmacokinetic value, because it was necessary for imaging of the abscess and tumor to take a long time.

[Infective endocarditis associated with vertebral osteomyelitis: report of two cases]

A 42-year-old man and a 65-year-old woman with infective endocarditis suffered onset of severe back pain. Magnetic resonance imaging and technetium-99 m bone scanning demonstrated osteomyelitis in the lumbar spine which is an unusual complication of infective endocarditis. The man was treated by antibiotics and finally aortic valve replacement and laminectomy with bone grafting. The woman had small patent ductus arteriosus and developed aortic regurgitation, but was treated by antibiotics and corset application with good result. The possibility of osteomyelitis in the lumbar spine should be considered in a patient with endocarditis complaining of severe back pain. The appropriate antibiotic therapy over a prolonged period is recommended.

[An elderly patient with Leriche syndrome complicated by congestive heart failure and rhabdomyolysis]

A 64-year-old man, who had had bilateral intermittent claudication and leg pain for five years, was admitted because of sudden onset of severe leg pain, and acute respiratory failure. Laboratory data showed markedly elevated serum CK of 73,050 IU/L, and urinary myoglobin of 430,000 ng/ml. A diagnosis of rhabdomyolysis was made. Renal dialysis was required for the next two days because of acute renal failure. The aortogram was performed on the 32nd day and disclosed complete obstruction of the abdominal aorta immediately distal to the bilateral renal arteries. Good collateral flow was noted to the popliteal arteries. On the 49th day, the patient successfully underwent extra-anatomical bypass surgery (axillo-bifemoral bypass). The mechanism of rhabdomyolysis in this elderly patient was discussed.

Sympathetic hyperactivity in patients with vasospastic angina--assessment by spectral analysis of heart rate and arterial pressure variabilities

The autonomic nervous system may play an important role in regulating coronary arterial tone. To evaluate the role of autonomic nervous activity in patients with vasospastic angina (VSA), we studied 10 VSA patients with patent coronary artery (mean; 56 yr, range; 44-66 yr) and 8 normal subjects (mean; 58 yr, range; 35-71 yr). ECG and arterial pressure were continuously recorded for 4 min in a supine position at 7:30 am, 10:30 am, and 4:30 pm. Low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.20 Hz) components of the beat-to-beat variabilities of the R-R interval (RRI) and systolic arterial pressure (SAP) were then estimated by autoregressive power spectral analysis. The LF-Normalized Power (LF-NP; [LF Power]/[Total Power]-[Direct Current Power]) of both the RRI and SAP variabilities were greater in VSA patients than in normal subjects (RRI: 0.51 +/- 0.07, 0.51 +/- 0.07, 0.53 +/- 0.06, vs 0.25 +/- 0.04, 0.31 +/- 0.05, 0.31 +/- 0.06, at 7:30 am, 10:30 am, and 4:30 pm respectively: p = 0.010, 0.044, 0.018. SAP: 0.62 +/- 0.06, 0.53 +/- 0.06, 0.57 +/- 0.06 vs 0.37 +/- 0.04, 0.30 +/- 0.06, 0.26 +/- 0.07, respectively: p = 0.006, 0.017, 0.003.). The LF-power of SAP variability also tended to be greater in VSA patients. There was no difference in the HF-component coefficient of variance (CCV (%) = 100 x (component power) (1/2)/ mean RR intervals) of the RRI variabilities between the 2 groups. These results indicate that increased sympathetic vasomotor tone and cardiac sympathetic predominance may play an important role in patients with VSA.

[Two cases of Candida endocarditis associated with abdominal disease]

Two cases of Candida endocarditis are reported. The first case was of a 63-year-old man who had a positive blood culture for Candida albicans during treatment for liver abscess and early gastric cancer. He was transferred to our department, and aortic and tricuspid regurgitation due to Candida endocarditis was diagnosed. The patient was successfully treated with aortic valve replacement, tricuspid valve plasty and anti-fungal agents. The second case was of a 65-year-old man who complained of fever. Despite a diagnosis of common bile duct cancer and resection of the tumor, the fever persisted. He was transferred to our department and was diagnosed having aortic regurgitation due to Candida endocarditis, complicated by heart failure. Although intense medical therapy including antifungal agents, diuretics, catecholamines and digoxin was initiated, the patient died from multiple embolisms 9 days later. In the treatment of Candida endocarditis, early diagnosis and early decision-making for either surgical or medical therapy is indispensable. Although the prevalence of Candida endocarditis is low, the differentiation of this disease should be taken into account in febrile elderly patients with long-standing therapy with antibiotics.

Vitamin K prodrugs: 2. water-soluble prodrugs of menahydroquinone-4 for systemic site-specific delivery

PURPOSE

The hydrochloride salts of the N,N-dimethylglycine esters of menahydroquinone-4 (1-mono, 1; 4-mono, 2; and 1,4-bis, 3) were assessed in vivo as prodrug for the systemic site-specific delivery system of menahydroquinone-4 (MKH), the active form of menaquinone-4 (MK-4, vitamin K2(20)).

METHODS

The disposition of MK-4 and menaquinone-4 epoxide (MKO) following the intravenous administration of the prodrugs and MK-4 preparation solubilized with surfactant (H-MK-4) were studied in vitamin K cycle inhibited rats. The relative bioavailability of MKH after the administration of the prodrugs was assessed from the area under the plasma concentration of MKO vs. time curve (AUCMKO). The specific delivery of MKH to its active site (liver) and coagulation activity after the administration of selected prodrug 1 were then compared with those of H-MK-4 in warfarin poisoned rats.

RESULTS

All compounds showed linear pharmacokinetics, and significant bioavailability of MKH was also observed following the administration of 1 (188%), 2 (87%) and 3 (135%). Prodrug 1 caused the following increases; AUCliver of MKO from 70.7 +/- 5.77 (H-MK-4) to 167 +/- 7.89 nmol.h/g, MRTliver of MKO, from 3.87 +/- 0.307 to 8.57 +/- 0.432 h. The liver accumulation of intrinsic 1 reached a maximum (88% of dose) by 0.25 h. The rapid and liver-selective uptake and liver esterase mediated MKH regeneration characteristics of 1 enhanced the delivery of MKH to its active site and the selective advantage was increased 5.7 fold. The coagulation activity was extended 1.9 fold by 1 administration.

CONCLUSIONS

The results indicated that these highly water-soluble and liver-esterase hydrolyzable ester derivatives of MKH are potential candidates for parenteral prodrugs which can thus achieve the systemic site-specific delivery of MKH. Such effective and selective delivery of MKH to its active site can therefore lead to enhanced pharmacological efficacy and can also avoid the toxicity induced by the solubilizing agent used in the H-MK-4 preparation.

[Prognosis of patients with triple vessel disease and old myocardial infarction: relationship to the number of total coronary occlusions]

Patients with myocardial infarction (MI) and triple vessel coronary disease generally have poor prognoses. However, it is not known whether there are particular angiographic variables associated with the poor prognosis in MI patients with triple vessel disease. The angiographic variables for poor prognosis were investigated in 43 MI patients with triple vessel disease (32 men and 11 women, mean age 63 +/- 9 years) who were followed medically for a mean of 32 +/- 28 months. There were 13 cardiac deaths (30%) and 10 late-coronary artery bypass grafting (23%). Twenty patients were alive and well. The patients who died of cardiac causes had lower ejection fractions (42 +/- 18% vs 49 +/- 15%, p < 0.05), a higher prevalence of two vessel occlusion (77% vs 40%, p < 0.05), and a higher prevalence of coronary occlusion opposite the MI site (69% vs 25%, p < 0.01) when compared to survivors, although there were no significant differences in age, MI sites, or the prevalence of occlusion in the infarct-related artery. Multivariate analysis with the Cox proportional hazards model revealed that coronary occlusion opposite the MI site (hazards ratio 16.36) and an age of > or = 65 years (4.46) indicated a significantly high ratio. The hazard ratio of the ejection fraction and two vessel coronary occlusion were not significant. The poor prognosis of MI patients with triple vessel coronary disease may be related to impaired left ventricular function and to coronary occlusion opposite the MI site and greater age. This may have important clinical implications in the initial decision for interventional therapy.

[Diagnosis and prognosis of elderly patients with coronary artery disease: assessment with dipyridamole thallium imaging]

Noninvasive evaluation of coronary artery disease is difficult in elderly patients because of their limited exercise-capacity. The diagnostic and prognostic value of dipyridamole perfusion scintigraphy was assessed in 147 patients aged 65 years and older. All patients underwent coronary angiography. Initially, 32 patients had percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). The other 115 patients were first treated medically and followed for a mean of 29 +/- 22 months. Nine patients (7.9%) had cardiac events including cardiac death and coronary intervention (PTCA or CABG) during the follow-up. Dipyridamole perfusion scintigraphy was performed safely in all patients, whereas treadmill exercise testing could not be adequately performed in 24 patients, 18 of whom had multivessel disease. Multiple regression analysis showed that: fixed defect and reversible defect were powerful detectors of coronary lesions (p = 0.0001, p = 0.0027, respectively), all patients with fixed disease and 94% of patients with only reversible defect had significant coronary lesion; Diffuse slow washout and ST depression were statistically significant for detecting multivessel coronary lesions in patients with fixed disease (p = 0.0001, p = 0.017, respectively), the sensitivity and specificity of diffuse slow washout and/or ST depression for detecting multivessel coronary lesions ware 85% and 74%, respectively, and ST depression was statistically significant for detecting multivessel coronary lesions (p = 0.0002) in patients with only reversible defect, the sensitivity and specificity of ST depression were 88% and 64%, respectively. Cox survival analysis identified diffuse slow washout as the best predictor of future cardiac events among the scintigraphic variables.(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of silent ischemia in dipyridamole perfusion scintigraphy: evaluation in patients with angina]

The significance of silent myocardial ischemia detected by dipyridamole perfusion scintigraphy was evaluated in 80 patients with stable angina and reversible defects (RD) but no infarction. The patients were divided into two groups: 26 patients with silent RD (62 +/- 7 years) and 54 patients with painful RD (65 +/- 7 years). Coronary risk factors, extent of coronary lesions, localization and degree of RD, and prognosis were compared. There was no significant difference in the incidence of coronary risk factors between these two groups, except for hyperlipidemia which was less frequently observed in patients with silent RD than in those with painful RD (8% vs 41%, p < 0.01). Coronary angiography revealed a higher prevalence of insignificant lesions or single vessel disease in patients with silent RD than in those with painful RD (73% vs 39%, p < 0.05). Dipyridamole perfusion scintigraphy revealed a lower degree of RD in patients with silent RD than in those with painful RD (4.4 +/- 3.3 vs 9.0 +/- 4.1 segments, p < 0.05), though there was no significant difference in the localization of RD between these two groups. Treadmill stress testing revealed a lower incidence of chest pain in patients with silent RD than in those with painful RD (26% vs 65%, p < 0.05), despite the mean exercise-duration being significantly longer in the former than in the latter (5.5 +/- 1.7 vs 3.9 +/- 1.7 min, p < 0.05). There was no significant correlation between the late peak serum ML-1 level and LV volume, and the size and motion of infarcted areas in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin K prodrugs: 1. Synthesis of amino acid esters of menahydroquinone-4 and enzymatic reconversion to an active form

The efficacy and toxicity of vitamin K depends on the pathway and the extent of enzymatic reductive activation to vitamin K hydroquinone, which is an essential cofactor for the synthesis of clotting factors. Parenteral use of vitamin K is impaired by its water insolubility. With the aim to improve delivery problems associated with menahydroquinone-4 (MKH, 2), an active form of menaquinone-4, N,N-dimethylglycine esters of 2 (1-mono, 4-mono, and 1,4-bis) were synthesized and assessed as potential water-soluble prodrugs for parenteral use. The esters can deliver the hydroquinone to its active site without a quinone reductive activation step. The hydrochloride salts of the esters were found to be quite soluble in water. The hydrolysis of the esters in 20% rat liver homogenate 9000 x g supernatant, rat plasma and phosphate buffer, pH 7.4, at 37 degrees C was kinetically studied in the presence and absence of an esterase inhibitor. The hydrolysis was catalyzed by esterases located in the rat liver and rat plasma and quantitatively yielded 2. These results suggest that esterification of 2 with N,N-dimethylglycine is a promising way for obtaining water-soluble prodrug forms of 2. Based on the high susceptibility to liver esterase, the esters are potential prodrugs for achieving the site-specific delivery of 2.

Prodrugs of vitamin E. 1. Preparation and enzymatic hydrolysis of aminoalkanecarboxylic acid esters of d-alpha-tocopherol

Nine aminoalkanecarboxylic acid esters of d-alpha-tocopherol were synthesized and evaluated as potential water-soluble prodrugs suitable for parenteral administration. The hydrochloric acid salts of the esters were soluble in water. The kinetics of hydrolysis of the esters was studied in isotonic phosphate buffer, rat plasma, human plasma, and rat liver homogenate at 37 degrees C. The hydrolysis of the esters was proved to be catalyzed by liver esterases. The susceptibility of the esters to undergo liver esterase hydrolysis was affected by the structure of the amino functionality and size of the acyl moiety on the promoiety. The N-methylaminoacetyl and N,N-dimethylaminoacetyl esters of d-alpha-tocopherol were more rapidly hydrolyzed than d-alpha-tocopheryl acetate, a commercially available d-alpha-tocopheryl ester. These results suggested that the salts of the N-methylaminoacetyl and N,N-dimethylaminoacetyl esters are promising prodrug candidates of d-alpha-tocopheryl for parenteral use.

Cationic technetium-99m complexes of N-substituted pyridoxal derivatives as renal function agents

New cationic technetium-chelating agents containing a pyridinium group have been synthesized and evaluated as potential renal radiopharmaceuticals.

METHODS

The pyridinium compounds used in the study are N-methyl pyridoxal chloride, N-ethyl pyridoxal chloride, N-propyl pyridoxal chloride, 1-methyl-3-hydroxy-4-formylpyridinium chloride, 1-methyl-2-formyl-3-hydroxypyridinium chloride and the Schiff's bases of N-methyl pyridoxal chloride with amino acid, amino acid ester and amino acid amide. Complexes of these chelating agents with 99mTc were prepared using a Na2S2O4 or a SnCl2 solution as a reducing agent. The purity of the 99mTc complexes was determined by paper electrophoresis in 0.1 M tris buffer.

RESULTS

Electrophoresis indicates slightly positive-charged species. The log P values of these complexes showed a hydrophilic nature. Urinary excretion of the 99mTc N-alkylated pyridoxal derivatives, 99mTc-diethylenetriaminepentaacetic acid, 99mTc-mercaptoacetylglycylglycylglycine (MAG3) and 131I-O-iodohippurate were determined in mice and rats at different time intervals. In a rat model, the pyridoxal-derived 99mTc complexes are rapidly excreted in urine and provide clear renal scintigrams. Hepatobiliary excretion was negligible, reducing scan interference from the intestines. Total clearances were lower than that of 131I-hippurate and 99mTc-MAG3.

CONCLUSIONS

The rate of urinary clearance of the new tracers was not significantly faster than 99mTc diethylenetriaminepentaacetic acid and the inhibitor N1-methylnicotinamide had only a minimal effect on the renal behavior. Though the new tracers have cationic properties, the pyridinium group did not contribute largely to the excretion of active transport.

Prognostic value of dipyridamole thallium scintigraphy in patients with coronary artery disease treated medically

To evaluate the prognosis of patients with coronary artery disease treated medically using dipyridamole thallium scintigraphy, 277 consecutive patients were followed prospectively. During 2.8 +/- 1.8 years of follow-up, 21 patients experienced nonfatal myocardial infarction or died from cardiac causes. Stepwise discriminant analysis using clinical and angiographic variables revealed that the combination of ejection fraction, number of diseased vessels, previous myocardial infarction and left ventricular asynergic score was most statistically significant (chi-square = 24, p = 0.0001) in predicting events. After including scintigraphic findings, the analysis revealed that the combination of negative washout rate, ejection fraction, ST depression during dipyridamole loading, previous myocardial infarction, coronary artery narrowing of > 90%, left ventricular asynergic score and number of diseased vessels (chi-square = 39, p < 0.0001) was the best predictor of events. These results indicate that the addition of dipyridamole thallium scintigraphic data to established angiographic markers can help better identify patients with coronary artery disease who are at high risk of cardiac events.

Regional thallium-201 washout and myocardial hypertrophy in hypertrophic cardiomyopathy and its relation to exertional chest pain

The mechanism of exertional chest pain in hypertrophic cardiomyopathy is uncertain, but may relate to myocardial ischemia. To study the mechanism of exertional chest pain in hypertrophic cardiomyopathy, dipyridamole-stress thallium-201 single-photon emission computed tomography was performed in 82 consecutive patients, and the 3-hour washout of thallium in relation to the tomographic image, regional wall thickness on echocardiography, and other clinical findings was analyzed. There was a weak inverse correlation of regional washout and wall thickness in 298 analyzed quadrant areas (r = -0.29; p = 0.0001). Twenty-five patients (31%) had history of exertional chest pain, and showed a significantly lower total washout and greater maximal left ventricular wall thickness than did those without chest pain (32 +/- 10% vs 37 +/- 9% [p = 0.03], and 27 +/- 7 vs 23 +/- 7 mm [p = 0.03], respectively). Even in mildly and nonhypertrophied areas, patients with chest pain had a significantly lower regional washout than did those without pain (33 +/- 10% vs 38 +/- 9%; p = 0.02), despite similar left ventricular wall thickness (12 +/- 2 vs 11 +/- 3 mm; p = NS). Reduced washout was strongly associated with exertional chest pain and was observed in myocardial regions that had normal as well as increased thickness, which indicates that this abnormality of thallium kinetics is a function of the disease process and not the magnitude of left ventricular hypertrophy.

Mechanisms of exercise limitation in hypertrophic cardiomyopathy

To assess the relation of exercise capacity to indexes of systolic and diastolic function in hypertrophic cardiomyopathy, 81 patients underwent two-dimensional echocardiography, technetium-99m equilibrium radionuclide angiography acquired in list mode and maximal, symptom-limited, treadmill exercise testing with measurement of maximal oxygen consumption (VO2 max). VO2 max for the group was 13.9 to 49.3 (mean 25.4) ml/min per kg. Thirty-six patients (44%) achieved less than or equal to 70% of age-predicted VO2 max. Patients with such a degree of limitation were more likely to be in New York Heart Association functional class II or III (23 of 36 vs. 14 of 45; p = 0.005); there was no such relation between VO2 and the incidence and magnitude of rest left ventricular outflow tract pressure gradient greater than 30 mm Hg (11 of 36 vs. 11 of 45; p = NS and 58 +/- 24 vs. 65 +/- 19 mm Hg; p = NS). In the 22 patients with a left ventricular outflow tract gradient, the ratios of peak ejection to peak filling rate and of atrial contribution to left atrial dimension were related to percent of the age-predicted VO2 max (r = 0.49, p = 0.02 and r = 0.54, p less than 0.02). These ratios reflect impaired left ventricular systolic performance and atrial systolic failure, respectively. Stepwise discriminant analysis revealed these two ratios to be the two strongest predictors (p = 0.0001) of patients with a left ventricular outflow tract gradient whose VO2 max was less than or equal to 70% of the age-predicted value (sensitivity 90%, specificity 100%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Significance of diffuse slow washout in dipyridamole loading thallium-201 myocardial perfusion scintigraphy]

To assess the significance of diffuse slow washout (DSW) in dipyridamole loading thallium-201 myocardial perfusion scintigraphy, 382 patients were studied. DSW were observed in 69 (24%) of 285 patients with perfusion defects, 5 (5%) of 97 patients without perfusion defects. There was significant relation between DSW and perfusion defects (p less than 0.01). Coronary angiography showed multivessel disease in 84% single vessel disease in 12% of patients with DSW and multivessel disease in 28%, single vessel disease in 50% of patients without DSW. During a mean follow up period of 29 months, initial CABG or PTCA were done in 41%, cardiac death occurred in 12%, nonfatal cardiac events occurred in 7% of patients with DSW and perfusion defects. In patients without DSW, initial CABG or PTCA were done in 11%, cardiac death occurred in 7%, nonfatal cardiac events occurred in 5%. Patients without perfusion defects had good prognosis regardless of the presence or absence of DSW. In conclusion, DSW indicates serious cardiac ischemia in patients with perfusion defects. DSW does not indicate cardiac ischemia in patients without perfusion defects.