Activation of CCK-B receptors elevates cytosolic Ca2+ levels in a pituitary cell line

Cytosolic Ca2+ levels ([Ca2+]i) in GH3 cells, a rat anterior pituitary tumor cell line, were monitored with fura-2 by fluorescence measurements. Cholecystokinin octapeptide (CCK-8) produced a transient elevation of [Ca2+]i. The elevation of [Ca2+]i by CCK-8 was inhibited by L-365,260, but not by devazepide. It was still observed when extracellular Ca2+ was eliminated, indicating that CCK-8 mobilizes Ca2+ from intracellular storage sites after interaction with CCK-B receptors. Cholecystokinin octapeptide increased the turnover of phosphatidylinositol, but it did not affect cyclic AMP levels. A possible involvement of phosphatidylinositol breakdown and calcium mobilization in the transduction system of CCK-B receptors in GH3 cells is suggested.

[Growth rates of aortic aneurysms as a risk factor in rupture: an evaluation with CT]

There is a lack of information on the rates of growth of aortic aneurysms. In the present study, the growth rates and survival rates of thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with aortic aneurysm managed nonoperatively have been followed more than 6 months with sequential X-ray computed tomography. The number of aneurysms was 211 (thoracic aortic aneurysm: 82, abdominal aortic aneurysm: 129). The growth rate of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/year, respectively. Aneurysms at the aortic arch (n = 34) grow at a higher average rate (0.56 cm/year) than aneurysms arising at other levels (p < 0.05). The survival rates showed the tendency that the higher the growth rate, the worse the survival rate. The survival rate of aortic arch aneurysm was significantly decreased when the growth rate was higher than the mean value. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with computed tomographic examination of size.

Arrhythmogenic right ventricular dysplasia: evaluation with electron-beam CT

The authors evaluated four cases of arrhythmogenic right ventricular dysplasia (ARVD) with electron-beam computed tomography (CT). Except for magnetic resonance imaging, non-invasive imaging techniques such as two-dimensional echocardiography and radionuclide angiography cannot always depict the abnormal morphology of the right ventricle. Definite diagnosis of ARVD requires the use of invasive cardiac cineangiography. Proper identification of right ventricular involvement in ARVD with CT helps in the diagnosis. Volume-mode CT clearly depicted an enlarged right ventricle with a scalloped surface of the free wall, conspicuous trabeculations with low attenuation, and abundant epicardial adipose tissue, which are characteristics of ARVD. Cinemode CT revealed reduced right ventricle function and abnormal wall motion. The authors propose that millisecond-order, electron-beam CT is a suitable noninvasive examination for evaluating the morphologic characteristics of the right ventricle and its function in ARVD.

GH3 cells, an anterior pituitary cell line, express CCK-B receptors

We found that GH3 cells, a rat anterior pituitary tumor cell line, expressed a single class of high-affinity binding sites for radiolabeled cholecystokinin octapeptide (CCK-8) with a Kd of 48 pM. The binding sites had high affinity for CCK-8, CCK-4, gastrin I, and L-365,260 (CCK-B antagonist), and had low affinity for devazepide (CCK-A antagonist), indicating that the binding sites are CCK-B receptors. GTP and its stable analogues inhibited radiolabeled CCK-8 binding to GH3 cell membranes, suggesting a coupling of CCK-B receptors to a G-protein.

[Detection of myocardial damage in patients with dilated cardiomyopathy using ultrafast CT]

The myocardial characteristics of DCM patients were investigated by ultrafast CT (UFCT), left ventriculography (LVG) and T1 myocardial scintigraphy (SCINTI). Late enhancement, focal wall thinning and intramyocardial fatty components were detected as focal abnormal findings by UFCT. The regions of asynergy detected by LVG and perfusion defect detected by SCINTI were well correlated with those of focal abnormal findings detected by UFCT. There were significant differences between patients with and without focal abnormal findings, in ejection fraction and end-diastolic pressure of left ventricle and the incidence of ventricular arrhythmia. It is possible that these focal abnormal findings represented focal ischemic myocardial damage in DCM patients. DCM patients were divided into two different functional groups by UFCT findings.

[Detection of myocardial fatty components with ultrafast CT]

Intramyocardial fatty components are sometimes depicted by CT of the thorax. However, no studies have investigated the distribution, frequency and cause of these components by using statistical analysis. Three hundred forty-five patients with various cardiac diseases were examined with an ultrafast CT scanner, and intramyocardial fatty components were detected in 15 (4.3%) of them. The frequency of intramyocardial fatty components in each disease was as follows: 6% in ischemic heart disease, 7% in Kawasaki disease, 11% in hypertrophic cardiomyopathy (HCM), 18% in dilated cardiomyopathy (DCM) and 33% in arrhythmogenic right ventricular dysplasia (ARVD). Except for patients with HCM, the segments of the ventricles, where the fatty components were detected, agreed well with the segments with asynergy in left ventriculography and/or the segments with perfusion defect in T1 myocardial scintigraphy. Thus, ischemic fatty degeneration was considered to be a main factor in the production of intramyocardial fatty components in these diseases. The focus of arrhythmia was sometimes detected in the segments with intramyocardial fatty components in DCM and ARVD cases. It is suspected that intramyocardial fatty components sometimes produce arrhythmia in these diseases.

Magnetic resonance imaging of pericardial malignant mesothelioma

Magnetic resonance imaging of pericardial malignant mesothelioma in two patients is reported. Magnetic resonance imaging clearly depicted the tumor location and expansion, and was useful in delineating the anatomic extent of pericardial malignant mesothelioma.

A pitfall in ultrafast CT scanning for the detection of left atrial thrombi

We studied 41 patients with mitral stenosis by ultrafast CT (UFCT) and transesophageal echocardiography to detect left atrial thrombi. Cardiac UFCT was performed twice after contrast medium injection to obtain early (during injection lasting 40-60 s) and late (approximately 5 min after beginning injection) phase images. There were 10 patients (24%) in whom a filling defect detected in the early phase disappeared in the late phase. The site of filling defects was the left atrial appendage in nine patients and the left atrium in one patient. All of the filling defects were in the ventral side of the left atrium. Furthermore, all of those patients had chronic atrial fibrillation. Transesophageal echocardiography revealed no thrombus in the area of the filling defect in the early phase. We believe that blood stasis existed in those patients. This finding leads to a false-positive result when only early phase images are obtained. The diagnosis of thrombi should be made only when a filling defect is observed in both phases. Late phase scanning is necessary in the diagnosis of left atrial thrombi.

Tetronothiodin, a novel CCKB receptor ligand, antagonizes cholecystokinin-induced Ca2+ mobilization in a pituitary cell line

We found a novel nonpeptide CCKB receptor antagonist, tetronothiodin (Ro 09-1468), in the culture broth of Streptomyces sp. NR0489. The structure of the compound (C31O8H38S), which has a 19-membered ring with an alpha-acyltetronic acid and tetrahydrothiophene moiety, is completely different from that of any known CCK receptor antagonist. Tetronothiodin inhibited [125I]CCK-8 binding to rat brain CCKB receptors with an IC50 of 3.6 nM, whereas it showed only weak affinity for rat CCKA receptors (IC50 = 70 microM). As demonstrated autoradiographically, tetronothiodin concentration dependently inhibited [125I]CCK-8 binding to CCKB receptors in rat forebrain slices. The effects of tetronothiodin on cytosolic Ca2+ concentrations in GH3 cells, a rat anterior pituitary tumor cell line, were investigated with the fura-2 method. Tetronothiodin inhibited CCK-8-induced Ca2+ mobilization without affecting basal cytosolic Ca2+ concentrations. In conclusion, tetronothiodin is a new, potent and highly selective CCKB receptor antagonist. It is a useful tool for investigating the pharmacological and physiological roles of CCKB receptors.

Critical degree of renal arterial stenosis that causes hypertension in dogs

The minimum degree of renal arterial stenosis needed to cause hypertension was identified by renal arterial angiography of anesthetized dogs. The effects of renal nerves and prostanoids on the critical stenosis were also examined. The left renal artery was constricted concentrically by a radiolucent constrictor device, and the stenosis of the artery was evaluated by cineangiography with the kidney either innervated or denervated. At this time, renal blood flow, renal perfusion pressure, and systemic blood pressure were serially monitored. In another group of dogs, renal venous and aortic blood samples were taken as the stenosis increased; these were assayed for prostaglandin E2 and plasma renin activity. The same experiments were done again after treatment with a cyclooxygenase inhibitor, aspirin DL-lysine (54 mg/kg). With the kidney either innervated or denervated, systemic blood pressure began to increase when the stenosis was more than 70% of the diameter of the renal artery; the renal blood flow decreased when the stenosis was more than 75% of the diameter. Aspirin treatment attenuated the increase in blood pressure but did not affect the autoregulation of the renal blood flow when stenosis was 70% or less. Prostaglandin E2 production increased in the stenotic kidney when the stenosis was more than 70%; aspirin inhibited prostaglandin synthesis and suppressed the stimulation of renin release. These results suggest that whether there is innervation or not, the critical degree of renal arterial stenosis that causes hypertension is more than about 70% of the diameter in the presence of renal prostaglandins; in their absence, the critical point above which hypertension occurs is 75% or more.

Aortic aneurysms: growth rates measured with CT

Because of a lack of information about the rates of growth of aortic aneurysms, such rates in thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with atherosclerotic aortic aneurysm managed nonoperatively were followed up for more than 6 months with sequential computed tomography (CT). There were 211 aneurysms (thoracic aortic, 82; abdominal aortic, 129). The growth rates of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/y, respectively. Aneurysms at the aortic arch (n = 34) grew at a faster average rate (0.56 cm/y) than aneurysms arising at other levels, even when the rate was corrected for the initial diameter. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with CT examination of size.

[Echocardiography-guided transseptal left atrial puncture: a safe approach to percutaneous transvenous mitral commissurotomy]

Transseptal left atrial puncture has generally been carried out under fluoroscopic control. In our experience, cardiac tamponade occurred in 3 of 83 cases during transseptal puncture for percutaneous transvenous mitral commissurotomy (PTMC) and percutaneous transvenous aortic valvuloplasty (PTAV). We tried to perform the puncture under simultaneous fluoroscopic and 2DE guidance to decrease the rate of complications. As a result, no complication has occurred in 55 cases. Furthermore, 2DE indicated that directing the puncture needle towards 4 or 5 o'clock was inappropriate, but that 3 o'clock was an appropriate direction for puncture of the fossa ovalis of a left atrium dilated because of mitral stenosis. In conclusion, transseptal left atrial puncture can safely and easily be carried out under a combination of fluoroscopic and 2DE guidance, as this procedure displays the correct position and direction of the needle tip for interatrial septal puncture.

Evaluation of myocardium in ischemic heart disease by ultrafast computed tomography

In this study we evaluated quantitatively the contrast enhancement of the myocardium of 27 patients with infarction and ischemia by ultrafast CT (Imatron C-100) with a scan time of 100 msec. We defined three parameters from the CT numbers of the myocardium and the ventricle in both the early and the late phase (about 4 min) after the injection of non-ionic contrast material; the difference of the CT numbers of myocardium between the early and the late phase (delta CT#), and the ratios of the CT numbers of the myocardium and the ventricular lumen (M/L) in both the early phase and the late phase. The delta CT# for myocardial infarction and severe ischemia were -20 +/- 10HU and -8 +/- 10HU, respectively. These values were significantly lower than the mild ischemic myocardium and normal myocardium (p less than 0.001). The average M/L values for myocardial infarction and ischemia in the early phase were 19 +/- 8% and 16 +/- 6%, respectively. These values were significantly lower than those in normal myocardium (p less than 0.001). The average M/L values for infarction and severe ischemia in the late phase were 90 +/- 18% and 63 +/- 20%, respectively. These M/L were significantly dissociated (p less than 0.001). Our results indicate that with contrast UFCT it is feasible to detect quantitatively the myocardial characteristics of ischemia and infarction.

Quantitative assessment of myocardial enhancement with iodinated contrast medium in patients with ischemic heart disease by using ultrafast x-ray computed tomography

BACKGROUND AND RATIONALE

The authors report the quantitation of myocardial enhancement using iodinated contrast medium in patients with ischemic heart disease. Twenty-eight patients with chronic ischemic heart disease and 11 controls were examined by ultrafast computed tomography (CT) using 100-msecond scans.

METHODS

The authors analyzed M/L (ratio of post-contrast incremental increases in the left ventricular myocardial and luminal CT number) in early and late phases after contrast injection.

RESULTS

In controls, mean values of early and late M/L were 30% and 51%, respectively. In infarcted or severely ischemic segments, early M/Ls (19%, 16%) were significantly small (P less than .001), whereas late M/Ls (90%, 63%) were higher (P less than .001, .01) than controls. Segments with infarction or severe ischemia were differentiated from mild or nonsignificant ischemia by using this parameter (sensitivity, 99%; specificity, 88%).

CONCLUSIONS

M/L is useful for detection of the ischemic myocardium.

[Growth rate of abdominal aortic aneurysms as measured by Computerized tomography]

To evaluate the growth rate of abdominal aortic aneurysms, sequential computed tomography (CT) examinations were performed on 125 nonoperated patients (M/F 101/24, mean age 67 +/- 8 years, 129 lesions) at intervals of at least 6 months. Growth rates of aneurysms were obtained by subtracting the first from the last diameter and adjusting for examination interval. Mean growth rate was 0.28 +/- 0.26 cm/year. Aneurysms with an initial diameter exceeding 4 or 5 cm showed significantly faster growth than smaller aneurysms. There was no significant correlation between growth rate and atherosclerogenic factors, but systolic blood pressure was significantly higher in patients whose aneurysms ruptured. Our study showed quantitatively that aneurysms with a large diameter have a rapid growth rate, the growth rate of infrarenal aneurysms is significantly faster than that of suprarenal aneurysms, and blood pressure control is important to prevent rupture.

Type A aortic dissection: evaluation with ultrafast CT

The authors examined 17 patients with type A aortic dissection with ultrafast computed tomography (CT). Forty sections with 1-cm intervals, from the aortic arch to the aortic bifurcation, were scanned serially without breath holding within only 74 seconds. Except for two thrombosed dissections, all intimal flaps in the ascending aorta were demonstrated, and 14 (93%) of the 15 surgically proved intimal tears were depicted. An intimal tear in the aortic arch was missed. Since conventional scanning tends not to depict type A aortic dissection, millisecond-order ultrafast CT scanning has the potential to become the modality of choice for imaging of aortic dissection.

RelB, a new Rel family transcription activator that can interact with p50-NF-kappa B

We have identified a serum-inducible gene, relB, which encodes a protein of 558 amino acids containing a region with high similarity to c-Rel and other members of the Rel family. Transcriptional activation analysis of GAL4-RelB fusion proteins in yeast cells reveals that RelB contains in its C-terminal 180 amino acids a transcriptional activation domain. The N-terminal part including the region of similarity with the Rel family shows no detectable transcriptional activity. RelB does not bind with high affinity to NF-kappa B sites, but heterodimers between RelB and p50-NF-kappa B do bind to different NF-kappa B-binding sites with a similar affinity to that shown by p50-NF-kappa B homodimers. However, RelB/p50-NF-kappa B heterodimers, in contrast to p50-NF-kappa B homodimers, transactivate transcription of a promoter containing a kappa B-binding site.

Evaluation of the susceptibility effect on gradient echo phase images in vivo: a sequential study of intracerebral hematoma

Susceptibility effect of intracerebral hematoma was estimated on the phase images of gradient echo (GrE). Thirty-five hematomas were studied 3 hr to 5 yr after the onset, a total of 72 times with use of phase and magnitude images of GrE, as well as T1-, T2-, and density-weighted spin-echo (SE) images at 1.5 T. On the basis of the theory of electromagnetism, phase shift to hematoma was calculated for simplified models with concentric distribution of paramagnetic susceptibility. All hematomas were well visualized by the phase images, the pattern of which changed sequentially. The distribution of paramagnetic susceptibility could be estimated by correlating the observed phase shifts with the calculated one. SE images were necessary to presume the type of magnetic substances. A probable hypothesis of the evolution of intracerebral hematoma is proposed.

Aspirin injection test to predict angioplasty outcome in unilateral renovascular hypertension: preliminary report

We examined the usefulness of aspirin DL-lysine for prediction of the outcome of renal artery angioplasty in renovascular hypertension. The study was carried out in eight hypertensive patients with unilateral renal artery stenosis: six were free from azotemia and two had slight azotemia. Before and 30 min after an intravenous injection of aspirin DL-lysine (18 mg/kg), renal venous and abdominal aortic plasma was sampled and assayed for prostaglandin E2 and plasma renin activity. Blood pressure and heart rate were serially measured at this time. Renal angioplasty was later performed and was technically successful in all patients. In the six patients without azotemia, aspirin inhibited renal prostaglandin E2 synthesis and suppressed renin release from the ischemic kidney, resulting in lowered blood pressure. Renal angioplasty caused plasma renin activity to become normal and lowered high blood pressure. The reduction in blood pressure by angioplasty was correlated with the responses of blood pressure and renin release to aspirin. However, in the two patients with azotemia, aspirin neither suppressed renin release nor lowered blood pressure. Their hypertension was not reduced by the angioplasty. These results indicate that an aspirin injection test could be useful for prediction of the outcome of angioplasty in unilateral renovascular hypertension.

[Evaluation of coronary artery calcification by ultrafast CT]

A preliminary study was performed to determine whether ultrafast computed tomography (UFCT) is useful as a noninvasive screening examination for predicting coronary artery disease (CAD). UFCT was used to detect coronary artery calcification in 31 patients with angina pectoris (AP) without myocardial infarction. Except for six patients with vasospastic AP, 22 out of 25 patients had detectable calcification in at least one vessel. SVD, DVD and TVD were detected in six of nine patients (67%), seven of seven (100%) and nine of nine (100%), respectively. Based on the findings of coronary calcification by UFCT, the sensitivity, specificity and predictive accuracy of angiographically significant stenosis (greater than 75%) were 94%, 71% and 78% for all branches, respectively. The calcification score for vessels with significant stenotic lesion (n = 48) was statistically higher (p less than 0.01) than that for vessels without stenotic lesion (n = 45). In conclusion, UFCT appears to be useful noninvasive screening examination for detecting CAD, although a prospective study in a large number of patients will be necessary to establish the value of this new method more reliably.

Late enhancement of the left ventricular wall in hypertrophic cardiomyopathy by ultrafast computed tomography: a comparison with regional myocardial thickening

Eight patients with hypertrophic cardiomyopathy (HCM) were examined by ultrafast computed tomography (UFCT) to investigate the relationship between late enhancement (LE) of the left ventricular (LV) wall after injection of contrast medium and the variations between minimum and maximum wall thickness of the LV. Late enhancement was usually found as a patchy, stained area in the myocardium on delayed phase volume mode images of UFCT. Out of 48 LV segments of the patients with HCM, 21 had LE. Normalized percentage regional wall thickening in the segments that had LE was significantly less than that in the segments that did not have LE (63.6 +/- 44.5% and 137.6 +/- 54.6%, respectively; p less than 0.001). This may reflect abnormal myocardial architecture.

[67Ga imaging in the patients with infective endocarditis after surgery for congenital heart disease]

67Ga imaging was performed in sixteen patients (age: 8 m.-18 y.) who had persistent fever and positive acute phase reactants after surgery for congenital heart disease. Abnormal uptake of 67Ga over the heart and the lungs was evaluated with a computer. Abnormal uptake of 67Ga was observed in seven patients, three of them showed it in the area of peripheral pulmonary artery and another four showed it in the area of artificial vessels for pulmonary artery reconstruction. In six patients with positive blood cultures, five showed abnormal uptake of 67Ga and in ten patients with negative blood cultures, two showed it. Vegetation was detected with 2D-echocardiography in four patients and all of them showed abnormal uptake of 67Ga, while in 12 patients without vegetation three showed it. In conclusion, 67Ga imaging was useful to detect the foci of infective endoarteritis or pulmonary embolism caused by the vegetation in infective endocarditis in the patients after surgery for congenital heart disease, especially in the peripheral pulmonary arteries and artificial vessels which could not be detected with 2D-echo.

Aspirin test for differentiation of unilateral renovascular hypertension from hyperreninemic essential hypertension

Responses of renin release and blood pressure to aspirin DL-lysine (ASP) were examined to find out if the responses could help in the differentiation between unilateral renovascular hypertension (RVH) and hyperreninemic essential hypertension (EHT). The two studies involved ten patients with unilateral RVH, eight with hyperreninemic EHT, and five with hyporeninemic EHT. In a radiological study, before and 30 min after an intravenous injection of ASP (18 mg/kg), renal venous and abdominal aortic plasma was sampled and assayed for prostaglandin (PG) E2 and plasma renin activity (PRA). Systemic blood pressure was measured serially. The reproducibility of the responses to ASP was confirmed in a bedside study. In unilateral RVH, ASP suppressed renin release from the stenotic kidney and reduced the renal vein PRA ratio to less than 1.5 via the inhibition of PG synthesis, which is accelerated in that kidney. The mean suppression of aortic PRA at this dose of ASP was 35% in these patients, and their blood pressure decreased in proportion to the suppression of PRA. However, in the two EHT groups, ASP elevated the mean blood pressure. The renal synthesis of PGE2 was inhibited by ASP in all patients, but the suppression of PRA, while small, was significant (19% in the aorta) in the patients with hyperreninemic EHT, and not significant in patients with hyporeninemic EHT. The different responses of blood pressure and PRA to ASP between RVH and EHT were reproducible in the bedside study.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute reduction of mitral valve area after percutaneous balloon mitral valvuloplasty: assessment with Doppler continuity equation method

Mitral valve areas before and after balloon mitral valvuloplasty were serially determined by the Doppler continuity equation method in 16 patients. Ultrasound examinations were performed before and immediately after balloon inflation and 24 hours, 1 week, and 1 month after valvuloplasty. Mitral valve area determined by the Doppler continuity equation method correlated well with that determined at catheterization by the Gorlin formula, not only before but also immediately after balloon inflation (y = 0.87 x + 0.05, standard error of estimate = 0.22 cm2, r = 0.90). Serial calculation of mitral valve area by the Doppler continuity equation method showed a slight but significant decrease in the valve area at 24 hours after balloon mitral valvuloplasty but no change after that. We conclude that the Doppler continuity equation method provides an accurate estimation of mitral valve area before and even after balloon valvuloplasty. Mitral valve area dilated by balloon inflation is decreased slightly within 24 hours after the procedure, which corroborates valve stretch as one mechanism for increasing mitral valve area with balloon valvuloplasty. Estimation of mitral valve area immediately after balloon mitral valvuloplasty may overestimate the long-term efficacy of the procedure.

A statistical trial of subclassification for tardive dyskinesia

The authors applied a statistical method to subclassify tardive dyskinesia (TD) in 71 psychiatric patients. Based on two-step statistical procedures and findings reported previously, TD is considered to consist of 2 subgroups: a classical dyskinesic group and a dystonic group. Symptoms manifested in the former group are seen most frequently in the oral region while the latter group, which is usually called tardive dystonia, is manifested by movement disorders in the trunk and extremities, predominantly. Abnormal movements occurring in the facial region characterize a population whose members may belong to either group.

Identification and structural analysis of a ribosomal RNA gene promoter from Thiobacillus ferrooxidans

The 5'-terminus of a rRNA operon (rrnT2) from Thiobacillus ferrooxidans was characterized. The rRNA promoters from this microorganism were identified by means of a functional assay in Escherichia coli. DNA sequencing of the promoter region, upstream the 16 S rRNA gene, showed the presence of a consensus sequence for bacterial ribosomal promoters. Other features such as a 'discriminator' sequence, antiterminator elements and an upstream hexanucleotide common to several rRNA operons were also found. Two other putative transcription promoters were also identified.

Evaluation of the susceptibility effect on the phase images of a simple gradient echo

The phase shifts of a simple gradient echo (fast low-angle shot) were correlated with the local change in resonance frequency due to the differences in susceptibility among tissues (susceptibility effect). Susceptibility effects were considered theoretically, and the phase shifts for spherical and cylindrical configurations were calculated. A 1.5-T magnetic resonance unit and phantoms filled with solutions of copper chloride in water were used to obtain the phase images. The phase shifts of the simple gradient echo coincided with the values calculated with use of the sum of the macroscopic magnetic field and the cavity field of Lorentz. The authors conclude that the gap of the phase shifts at interfaces of tissues is useful in the evaluation of differences in magnetic susceptibility among tissues.

Significance of ultrafast computed tomography in cardiac imaging: usefulness in assessment of myocardial characteristics and cardiac function

The usefulness of cardiac ultrafast computed tomography (CT) is discussed in this article. Thirty-three patients with ischemic heart disease and 15 patients with hypertrophic cardiomyopathy were assessed for myocardial characteristics, while 30 patients with various heart diseases were assessed for cardiac function. Volume mode (100 msec scan) and cine mode (50 msec scan) studies were applied. As the findings of abnormal myocardial characteristics, early defect (ED) and late enhancement (LE) of the left ventricular (LV) wall were observed after injection of contrast medium. In ischemic heart disease, all 27 patients with myocardial infarction (MI) and all 16 MI sites showed LE, while 25 ED sites were well correlated with MI or significant coronary stenosis. LE was quite sensitive for MI and ED was highly predictive for ischemia. Seven of 15 HCM patients (47%) also showed LE, indicating that LE occurs in tissues with a different capillary architecture from that observed in normal myocardium. For evaluation of cardiac function, ventricular volumetry was performed by summation of a sliced area of the ventricles. End-diastolic volume and LV ejection fraction calculated by this means correlated excellently with the values obtained using left ventriculography (R = 0.97 and 0.96). The stroke volumes for both ventricles were nearly equal when calculated using ultrafast CT. Consequently, the study of cardiac volumetry using ultrafast CT was thought to be reliable and utilizable in clinical practice.

[Ultrafast CT scanner; preliminary experience in Japan]

We evaluated the usefulness of Ultrafast CT scanner C-100 (UFCT) in 30 patients' clinical practice. UFCT was very useful not only for cardiac studies but for other body organs' studies. Simultaneous multilevel ultrafast scans of UFCT enabled us to analyse cardiac ventricular motion not only by the ejection fraction but by the change of wall thickness. We could get ultra-early contrast phase images (within one minute images from contrast medium injection start) of contiguous 15, 1 cm interval levels by high quality single slice mode of UFCT. These ultra-early phase images and late phase images would be helpful for tissue characterization.

[Evaluation of aortic dissection by ultrafast computed tomography]

We report usefulness of ultrafast CT (UFCT) in evaluation of aortic dissection, according to the results of examination of 51 patients. By volume mode study of UFCT, aortic dissection was diagnosed in all patients. Fine structures such as intimal tear and ulcer-like projection were depicted in detail. Pulsatile movement of true and false channels was detected by cine study. Precise flow analysis of both channels was available by flow mode study of UFCT. In morphological and functional assessment of aortic dissection, UFCT is superior to conventional scanners, and may be preferable to DSA or MRI.

[Clear visualization of the tracheobronchial tree in complex congenital heart disease using digital subtraction fluorography]

We knew that digital subtraction fluorography (DSF) could clearly visualize the tracheobronchial tree by the respiratory movement. We applied DSF for 54 patients of complex congenital heart disease. In the visualization of the tracheobronchial tree, DSF was significantly superior as compared with the plain chest radiography (p less than 0.01). As this method needs to anesthetize patients to suppress their body movements, there might be some limitation to apply it for routine diagnostic workup. However, noninvasiveness and readiness of diagnosis justifies this method as an optional examination for confirming thoracic situs of complex congenital heart disease.

Improvement in mitral flow dynamics during exercise after percutaneous transvenous mitral commissurotomy. Noninvasive evaluation using continuous wave Doppler technique

Evaluation of mitral flow dynamics during exercise is critically important in patients who receive percutaneous transvenous mitral commissurotomy (PTMC) because limited mitral flow during exercise provokes hemodynamic deterioration and involves cardiogenic symptoms in patients with mitral stenosis. To examine mitral flow dynamics during exercise, we applied continuous wave Doppler technique in 20 patients with mitral stenosis. Exercise Doppler study was performed 2 days before and 5 days after PTMC. PTMC increased mitral valve area from 1.0 +/- 0.3 (mean +/- SD) to 1.9 +/- 0.5 cm2 and decreased mean transmitral pressure gradient from 8 +/- 2 to 4 +/- 1 mm Hg at rest. Moreover, PTMC decreased mean transmitral pressure gradient from 21 +/- 6 to 11 +/- 4 mm Hg at submaximal exercise. The extent of an increase in mitral valve area by PTMC correlated with a decrease in the mean transmitral pressure gradient at the submaximal exercise (r = -0.76, p less than 0.01) and that at rest (r = -0.52, p less than 0.05). Heart rate after PTMC during exercise was significantly lower than that before PTMC, indicating that the compensatory mechanism (tachycardia) to increase cardiac output during exercise is less necessary after PTMC. Thus, we conclude that the mitral flow dynamics during exercise is improved, as well as the resting mitral flow dynamics 5 days after PTMC, and that exercise Doppler study enabled us to make a noninvasive evaluation of the mitral flow dynamics in patients who receive PTMC.

Aspirin lowers blood pressure in patients with renovascular hypertension

To clarify the role of renal prostanoid in hyperreninemia and high blood pressure in human renovascular hypertension, we measured prostaglandin E2 and renin activity in renal venous and abdominal aortic plasma before and after the intravenous administration of the cyclooxygenase inhibitor, aspirin DL-lysine. Subjects were six patients with unilateral renovascular hypertension and six with essential hypertension. In patients with renovascular hypertension, prostaglandin E2 concentration in renal venous plasma from the stenotic kidney was 9.25 +/- 1.48 pg/ml, which was significantly higher (p less than 0.01) than the concentration in the renal venous plasma from the normal kidney (4.97 +/- 1.02 pg/ml) or in the aortic plasma (2.59 +/- 0.15 pg/ml). Plasma renin activity was also higher in the renal vein of the stenotic kidney than in the other two sites. The stenotic side/normal side ratio of the renal venous prostaglandin E2 correlated significantly with a renin ratio greater than 1.5 (r = 0.8211, p less than 0.05). Intravenous injection of aspirin DL-lysine (18 mg/kg) 30 minutes later markedly suppressed prostaglandin E2 and renin levels at all sites and clearly lowered arterial blood pressure (mean: from 120 +/- 6 to 110 +/- 5 mm Hg, p less than 0.01). The reduction in blood pressure correlated significantly with the suppression of plasma renin activity in the aorta (p less than 0.05) and in the renal vein of the stenotic kidney (p less than 0.01). Conversely, in patients with essential hypertension, aspirin had little effect on renin levels and increased mean blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial assessment of myocardial infarction by using gated MR imaging and Gd-DTPA

In order to assess the usefulness of Gd-DTPA in the evaluation of myocardial infarction, 17 patients were examined with gated MR imaging. Scans were made by using a spin-echo pulse sequence before and after IV administration of 0.15 mmol/kg of Gd-DTPA. The images were made at four intervals (average of 5, 12, 30, and 90 days) after the onset of the infarction. Gd-DTPA uptake at the infarcted area was graded as marked, moderate, or no increase in signal intensity by visual inspection. At these four time intervals, an area of increased signal intensity in the infarcted myocardium was detected on T1-weighted images after administration of Gd-DTPA in 14 (82%) of 17 cases, 16 (94%) of 17 cases, six (38%) of 16 cases, and three (21%) of 14 cases, respectively. Markedly increased signal intensity in infarcted areas was shown on T1-weighted images with Gd-DTPA at 5 and 12 days. The ratio of gadolinium uptake in the infarcted area to that in normal myocardium also was evaluated. At 5 and 12 days, the mean increase in signal intensity in the infarcted area was significantly higher than that in a normal area, but not at 30 and 90 days. Increased signal intensity also was apparent on T2-weighted images without Gd-DTPA at 5 and 12 days; however, the use of late echo reduced the signal-to-noise ratio, leading to image degradation. Uptake of Gd-DTPA was a positive marker in acute myocardial infarction, but no significant uptake of Gd-DTPA occurred in chronic myocardial infarction.

Cerebral vascular malformations: applications of magnetic resonance imaging to differential diagnosis

Twelve patients with cerebral vascular malformations (5 cavernous angiomas, 1 thrombosed arteriovenous malformation, and 6 venous angiomas) were studied with magnetic resonance (MR) imaging. All lesions were clearly depicted. Characteristic MR findings were obtained mainly on T2-weighted images: a markedly low intensity area was always seen. The margins of arteriovenous malformation (AVM) and venous angioma were irregular while those of cavernous angioma were smooth in all planes on T2-weighted images. Gradient-echo (GrE) pulse sequences were more sensitive than T2-weighted spin echo (SE) in lesion detection. MR imaging could play an important role in the differential diagnosis of cerebral vascular malformations.

[Gallium-67 imaging in patients with myocarditis in childhood and youth]

Gallium-67 (Ga-67) myocardial imaging was performed in 19 patients (1 month to 21 years of age) with proven or suspected myocarditis. The anterior images, 48 hrs after the intravenous administration of 0.5-2.0 mCi Ga-67 citrate, were analysed using a computer. Regions of interest were set on the heart, lungs and background, excluding the sternum and vertebrae. The uptake of Ga-67 was evaluated quantitatively by the ratio of the average count of the heart to the average count of the lung (H/L). When the H/L value was higher than 130% the cardiac uptake of Ga-67 was designated positive. Histological examination was performed in 11 patients who underwent right endomyocardial biopsy. The patients were categorized according to their clinical findings. Group 1 consisted of 11 patients with clinical symptoms of dilated cardiomyopathy, six of whom had arrhythmias or elevated serum CPK-MB levels (group Ia) in the acute stage of the disease, and the remaining five had neither (group Ib). Group 2 consisted of eight patients with dysrhythmias but without heart failure. Four had elevated serum CPK-MB levels (group IIa), but the remaining four did not (group IIb). All patients in the group Ia had positive Ga-67 uptakes, and three patients in the group Ib had negative uptakes. The H/L values were significantly higher in the group Ia than in the group Ib (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

[Magnetic resonance imaging of cerebrovascular disorders; cerebral infarction]

Patients with cerebral infarction and with suspicion of cerebral infarction were studied with magnetic resonance imaging (MRI) and correlative CT scans. MRI was more sensitive than CT for detecting cerebral infarction, and T2-weighted spin echo pulse sequence was most sensitive in the diagnosis of cerebral infarction except some lacunar infarctions and some cortical and subcortical infarctions. MRI using Gd-DTPA was more sensitive than contrast CT for detecting fresh infarcted areas, especially in the cases with multiple cerebral infarcted areas and cortical and subcortical infarcted areas, and many offer some informations in evaluating the state of circulation.

Mortality rate of schizophrenic patients with tardive dyskinesia during 10 years: a controlled study

We examined mortality rates (MR) during 10 years between schizophrenic inpatients with and without tardive dyskinesia (TD). The TD group had a significantly higher MR (41%), as compared with the control group (20%). However, we could not reveal critical factors to explain why the TD patients had the higher MR.

Characterization of the two rRNA gene operons present in Thiobacillus ferrooxidans

The organization of rRNA genes from the autotrophic, acidophilic bacterium Thiobacillus ferrooxidans has been examined. Two rRNA operons were found in this microorganism by means of genomic hybridization studies. Recombinant plasmids, pTR-3 and pTR-1 that carry a portion of 16/23 S rDNA from one operon and the 5'-flanking region of the second operon, respectively, were identified and characterized.

Rapid reduction of plasma atrial natriuretic peptide levels during percutaneous transvenous mitral commissurotomy in patients with mitral stenosis

To clarify the direct contribution of the left atrial pressure to secretion of human atrial natriuretic peptide (hANP), we have attempted to study the relations between plasma hANP levels, neurohumoral factors, and hemodynamic changes in 13 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). After PTMC, the left atrial pressure fell from 14.7 +/- 1.9 (mean +/- SEM) to 6.5 +/- 0.7 mm Hg in all patients studied (p less than 0.0005), whereas there were no remarkable changes in either the right atrial pressure, mean arterial pressure, or heart rate. Plasma immunoreactive hANP levels obtained from the pulmonary artery decreased from 278 +/- 51 to 137 +/- 31 pg/ml after PTMC (p less than 0.0005). There was a significant correlation between the decrement of hANP levels and that of left atrial pressure (r = 0.72, p less than 0.005). Neither plasma renin activity nor norepinephrine levels changed. In contrast, plasma aldosterone concentrations significantly increased from 11.3 +/- 1.5 to 16.4 +/- 2.7 pg/ml after PTMC (p less than 0.01), although there was no casual relation between plasma concentrations of aldosterone and hANP. The present result with PTMC-induced rapid fall of the left atrial pressure with a concomitant reduction in hANP secretion strongly suggests the importance of the left atrial pressure on hANP secretion in humans.

Comparison of ionic and nonionic low-osmolar contrast media in coronary arteriography. A crossover study in children

Twenty-six patients with Kawasaki disease were observed in a prospective crossover study to compare coronary arteriography with a nonionic low-osmolar contrast medium, iopamidol 370 mgI/mL, and with an ionic low-osmolar contrast medium, ioxaglate 320 mgI/mL. A slight heart rate change and no severe arrhythmia during coronary arteriography were observed with both agents. Electrocardiographically, QTc elongation and ST-T changes were marked in ioxaglate and minimal in iopamidol. No ventricular fibrillation occurred with either agent. Both contrast media provided adequate visualization for the diagnosis of Kawasaki disease, but the contrast of the images and the visualization of details were better with iopamidol than with ioxaglate. Iopamidol seems to be superior to ioxaglate in pediatric coronary arteriography.

[Comparisons of images simultaneously documented by digital subtraction coronary arteriography and cine coronary arteriography]

Using an angiography apparatus capable of simultaneously processing digital subtraction angiograms and cine angiograms, the diagnostic capabilities of both methods for the coronary arteries (DSCAG and Cine-CAG) were compared. 1. Twenty stenotic lesions of the coronary arteries of 11 patients were evaluated using both modalities. The severity of stenosis using DSCAG with a 512 x 512 x 8 bit matrix was semiautomatically measured on the cathode ray tube (CRT) based on enlarged images on the screen of a Vanguard cine projector which were of the same size as those of or 10 times larger than images of Cine-CAG. The negative and positive hard copies of DSCAG images were also compared with those of Cine-CAG. The correlation coefficients of the severity of stenosis by DSCAG and Cine-CAG were as follows: (1) the same size DSCAG images on CRT to Cine-CAG, 0.95, (2) 10 times enlarged DSCAG images on CRT to Cine-CAG, 0.96, and (3) the same size DSCAG images on negative and positive hard copies to Cine-CAG, 0.97. The semiautomatically measured values of 10 times enlarged DSCAG images on CRT and the manually measured values of the same size negative and positive DSCAG images in hard copy closely correlated with the values measured using Cine-CAG. 2. When the liver was superimposed in the long-axis projection, the diagnostic capabilities of DSCAG and Cine-CAG were compared. The materials included 10 left coronary arteriograms and 11 right coronary arteriograms. Diagnostically, DSCAG was more useful than Cine-CAG in the long-axis projection.

Magnetic resonance imaging of cerebral infarction: time course of Gd-DTPA enhancement and CT comparison

Thirty-five patients (7 females and 28 males) with cerebral infarction and suspicion of cerebral infarction of 4 h to 27 months duration were studied 45 times with magnetic resonance (MR) imaging using Gd-DTPA. Spin echo (SE) images were obtained before and after the administration of Gd-DTPA (0.1 or 0.15 mmol/kg) and compared with the enhanced CT. MR imaging using Gd-DTPA was more sensitive than enhanced CT and very useful for detecting a new focus of cerebral infarction, especially in the cases with multiple infarcted areas and for showing the extent of cortical and subcortical infarction. In most cases the MR enhancement was obvious in the subacute stage, especially after cerebral embolism, and the signal intensity of the lesion tended to show a gradual increase. The diagnosis of embolism was accepted on the basis of acute onset without prior TIA, coupled with angiography showing the embolus itself and/or a capillary blush and a wide area of infarction.

Inhibition of mitogen-stimulated T lymphocyte proliferation by calcitonin gene-related peptide

The effect of calcitonin gene-related peptide (CGRP) on mouse lymphocyte proliferation stimulated by mitogens was studied. CGRP (10(-10)-10(-7) M) dose-dependently inhibited the proliferative response of mouse lymph node cells and spleen cells stimulated by T cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA), whereas a B cell mitogen lipopolysaccharide (LPS) did not inhibit this response. The maximal inhibition by this peptide was 50% to 80% at 10(-8) and 10(-7) M. The addition of 10(-8) and 10(-7) M CGRP to lymph node cell cultures 24 hr after stimulation with Con A or PHA also had a significant inhibitory effect on the proliferative response. Furthermore, in the same concentration range (10(-10)-10(-7) M) CGRP increased intracellular cyclic AMP concentration in nylon wool nonadherent cells, but not in nylon wool adherent cells. CGRP had no significant effect on intracellular cyclic GMP concentration. In addition, specific binding of CGRP was observed in mouse spleen cells. Our present study suggests that CGRP inhibits the proliferative response of T lymphocytes to the mitogens by interacting with cell receptors coupled with adenylate cyclase. CGRP may be implicated in the regulation of T cell function.