A very small juxtaglomerular cell tumor preoperatively identified by magnetic resonance imaging

We describe a 31-year-old man. Although the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were elevated, computed tomography and rapid sequence pyelography disclosed no abnormality. However, based on the findings of the small tumor (8 x 8 mm) in the kidney visualized by magnetic resonance imaging (MRI) and excessive PRA in the right renal vein, tumor resection was performed. The positive immunohistochemical staining of renin and the visualization of renin mRNA by in situ hybridization provided evidence supporting the diagnosis of juxtaglomerular cell tumor. Blood pressure, PRA, and PAC were normalized after the surgery. The observations suggest that MRI is a powerful diagnostic procedure in small juxtaglomerular cell tumor.

Serial changes of left atrial thrombus in mitral stenosis: transesophageal echocardiographic studies in candidates for balloon mitral commissurotomy

BACKGROUND

Little is known concerning therapeutic modification of left atrial thrombus in mitral stenosis and its formation after successful balloon valvuloplasty (percutaneous transvenous mitral commissurotomy [PTMC]).

OBJECTIVE

To test the roles of the clinical use of anticoagulant therapy and PTMC, serial changes in left atrial thrombus were examined by transesophageal echocardiography in 80 patients with mitral stenosis.

RESULTS

No difference in embolic history, New York Heart Association functional class, cardiac rhythm, left atrial size or mitral valve area was found between patients with (n=23) and without (n=57) left atrial thrombus. Diuretic use was the prevalent factor for left atrial thrombi, which were dissolved completely in seven (30.4%) and partially in eight (34.7%) of the patients by adequate warfarin. However, after PTMC (n=53), newly formed thrombus was observed in four of 51 (7.8%) patients, which correlated with left atrial size (at least 50mm), atrial fibrillation and poorly controlled warfarin (thrombo test: 63.8 +/- 18.8% versus 35.9 +/- 17.7%, P<0.005). The newly formed thrombi were dissolved within several weeks.

CONCLUSION

Left atrial thrombus in symptomatic mitral stenosis exhibits elusive characteristics and should be strictly monitored even after successful PTMC by transesophageal echocardiography in order to achieve adequate anticoagulation.

Influence of cluster formation of acidic phospholipids on decrease in the affinity for ATP of DnaA protein

DnaA protein is the initiator of chromosomal DNA replication in Escherichia coli. We examined the influence of artificial mixed membrane composed of synthetic acidic (phosphate) lipid and basic (ammonium) lipid on the affinity of DnaA protein for ATP. Two sets of acidic and basic lipids with distinguishable numbers of hydrophobic alkyl chains were devised. Synthetic membranes made of the sole acidic lipid but not the basic bilayers inhibited the ATP binding to DnaA protein and stimulated the release of ATP from the ATP-DnaA complex. The basic bilayer-forming compounds served as the matrix for the guest acidic lipids. Acidic lipids dispersed in the basic matrix membrane had little effect on ATP binding and on ATP release. Conversely, acidic lipids forming cluster structures in the mixed artificial membranes inhibited the ATP binding and stimulated the release of ATP. These observations suggest that in mixed lipid bilayers, a cluster structure of acidic lipids seems to be an important parameter to decrease the affinity of DnaA protein for ATP.

[Prediction of left ventricular functional recovery in patients with acute myocardial infarction using single photon emission computed tomography with thallium-201 and iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid]

The relationships between myocardial perfusion, fatty acid metabolism, and cardiac function were investigated using dual single photon emission computed tomography (SPECT) with thallium and iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) during the acute (10 +/- 1 days) and recovery (60 +/- 14 days) phases in 29 patients with acute myocardial infarction. There were 18 patients who underwent successful primary coronary angioplasty (PTCA group) and 11 patients who received conservative therapy (non PTCA group). Thallium and BMIPP uptakes were scored visually by a 4-point system and left ventricular ejection fraction (LVEF) was calculated by radionuclide ventriculography. Although significant positive correlations between thallium and 123I-BMIPP scores were observed during both phases, BMIPP scores were significantly lower than thallium scores in both acute and recovery phases in the PTCA group. No significant difference in thallium and 123I-BMIPP scores was observed at the recovery phase in the non PTCA group. LVEF significantly correlated with thallium and 123I-BMIPP scores in both phases in the PTCA group. Furthermore, the difference between thallium and 123I-BMIPP scores during the acute phase significantly correlated with the improvement of LVEF during the follow-up period in the PTCA group (y = 0.92x-0.77, r = 0.65, p < 0.005). These findings suggest that mismatch of perfusion and metabolism in infarcted myocardium assessed by thallium and 123I-BMIPP SPECT is increased by reperfusion therapy and persists at least until the recovery phase of myocardial infarction. The recovery of left ventricular function depends on the extent of the mismatched uptake, indicating a predictor for functional recovery following acute myocardial infarction.

Isolation and characterization of inhibitory factors of DNA polymerase III holoenzyme from Escherichia coli

We isolated fractions by Mono Q chromatography that inhibited the activity of Escherichia coli DNA polymerase III holoenzyme using an assay system with a primed single-stranded DNA template coated with single-stranded DNA binding protein (SSB). The inhibitory activities were inactivated by heat-treatment at 100 degrees C for 10 min, suggesting that they are proteins. The factors did not inhibit the activity of RNA polymerase of Escherichia coli. The inhibitory effects were less potent for the activities of the large (Klenow) fragment of DNA polymerase I and T4 DNA polymerase than for DNA polymerase III holoenzyme. No degradation of single- or double-stranded DNA was observed in the fractions, indicating that inhibition was not due to degradation of the DNA.

[A report of successful surgical management of right coronary artery to right atrium fistula forming giant aneurysms at the posterior wall of the right atrium]

A 52-year-old woman was diagnosed by echocardiography to have a fistula of the right coronary artery (RCA) and the right atrium (RA). Aortography demonstrated a remarkably dilated and undulating fistulous tract originating from the region corresponding to the orifice of the normal RCA. The fistulous tract detoured to the posterior wall of the RA, and forming 2 aneurysms there, opened to the RA. A RCA of normal size originating midway of the fistulous tract was also observed. The patient was operated on under cardio-pulmonary bypass. Aortocoronary saphenous vein graft to the RCA having normal diameter was performed, and the RCA was ligated in the proximal side of the anastomosis. The orifice of the fistulous tract from the aorta was closed with a patch and the entrances into the RA were also closed by pledgetted mattress sutures. The post operative course was uneventful and the patient is now doing well without any complaints.

Classification of signals for blocking apoptosis in vascular endothelial cells

The survival and death of human umbilical vascular endothelial cells in culture are affected by several factors, such as fibroblast growth factor (FGF), serum, phorbol ester (TPA), and vanadate. In order to identify common aspects of the various signal-transduction processes during the course of apoptotic or programmed cell death, we designed experiments to distinguish between these factors in terms of the pathway that is responsible for the processing of each stimulus. We found, for example, that the effect of removal of FGF was specifically overcome by the addition of the phorbol ester. Our results indicated that two distinct pathways were operative, one specific for signal transduction initiated by FGF and phorbol ester and another specific for signal transduction initiated by serum and vanadate. These two pathways merged down-stream of the individual signal-processing pathways.

[Quantification of reversible perfusion abnormality using exercise-stress thallium SPECT before and after coronary revascularization]

Reversible myocardial perfusion abnormality was quantified by bull's eye and unfolded surface mapping methods in exercise thallium SPECT before and after coronary revascularization in 47 patients with angina pectoris, including 34 patients with previous myocardial infarction (PMI) and 13 with effort angina (AP). There was no difference in the incidence or extent of myocardial ischemia between the 2 groups before revascularization. However, the ischemic scores were significantly smaller in PMI group preoperatively than the reductions of the ischemic scores after revascularization. The ischemic scores, preoperatively estimated reversible perfusion abnormality was 32%, 69% and 48% of the improvement of the ischemic score (extent score, severity score, and ischemic area, respectively). Using the 3 ischemic scores, the improvement of perfusion abnormality was well predicted in 70-89% of AP patients but 35-57% of PMI patients. Thus, quantitative analysis in stress thallium SPECT is useful for detecting myocardial ischemia and evaluating the effect of coronary revascularization. However, about a half of myocardial viability was underestimated in one third of PMI patients by the conventional exercise-stress thallium SPECT study.

Studies on percutaneous transvenous mitral commissurotomy using a modified transseptal approach

A modified version of Brockenbrough's trans-septal catheterization technique was carried out in 11 patients indicated for percutaneous transvenous mitral commissurotomy (PTMC). In 8/11 (72.7%), a coiled guide-wire was successfully inserted through the foramen ovale without atrial septal puncture. The Brockenbrough needle was used merely to maintain stiffness and the orientation of the dilator. PTMC was performed with an Inoue single balloon without incident. Patent foramen ovale was found by transesophageal echocardiography prior to the operation in only 1/11 patients (9.0%); nonetheless, it proved not to be a critical factor for the success of the procedure. This procedure seems to have much potential to enable the treatment of mitral stenosis with a lowered risk to the patient, as long as it is performed with precision and caution.

[Correlation of regional wall motion and fatty acid metabolism in coronary artery disease, hypertension, and hypertrophic cardiomyopathy: assessment by dual-isotope SPECT with thallium-201 and iodine-123 beta-methyl fatty acid analogue]

In order to investigate the correlation between cardiac fatty acid metabolism and regional wall motion, dual-isotope tomography using thallium-201 and iodine-123 labeled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP), was performed in 15 patients with coronary artery disease (CAD), hypertension, or hypertrophic cardiomyopathy (HCM). The uptake of thallium and BMIPP was scored and compared with left ventricular regional wall motion assessed by 2-dimensional echocardiography and radionuclide ventriculography. The incidence of a complete agreement of thallium and BMIPP scores was significantly higher in hypertension (64%) and CAD (63%) groups compared to HCM patients (24%), while a lower BMIPP uptake compared to that of thallium (mismatching) was observed more frequently in HCM (65%) than in hypertension (31%) or CAD (33%). Only 3 infarct patients had regional wall motion abnormality which was detected in 20 (95%) of 21 segments with a low BMIPP uptake. Furthermore, compared to thallium perfusion, decreased BMIPP uptake much more corresponded to reduced wall motion in 8 of 11 segments with mismatching. Thus, metabolic abnormality assessed by BMIPP is well associated with asynergy in CAD patients, whereas the discrepancy of fatty acid metabolism and contraction is more dominant in HCM, suggesting that the combined assessment of thallium perfusion, BMIPP uptake, and regional wall motion might contribute to better understanding the pathogenesis of various cardiac disorders.

[Experimental study of indirect lymphography with iodinated starch]

Opacification of lymph nodes on CT was attempted by means of indirect lymphography with iodinated starch (IS). Sixty percent solutions of two different molecular weights of IS were prepared (5,000 mol wt and 70,000 mol wt in average). After subcutaneous injection of IS solutions to the pedal area of dogs, CT scans were performed to evaluate opacification of the popliteal lymph nodes. The lymph nodes began to be opacified from 10 min after the injection of each solution. The high molecular weight IS showed higher attenuation and longer duration of opacification than did the low molecular weight IS. Homogeneity of opacification was better with latter. The optimum molecular weight for this purpose is considered to be between 5,000 and 70,000 mol wt.