Mechanism for abnormal thallium-201 myocardial scintigraphy in patients with left bundle branch block in the absence of angiographic coronary artery disease

Patients with left bundle branch block (LBBB) often show abnormal images on exercise thallium (T1)-201 scintigraphy without evidence of significant coronary stenosis. We investigated the mechanism for this phenomenon. Six patients with LBBB and without significant coronary stenosis underwent T1-201 SPECT, ECG-gated SPECT imaging with Tc-99m-methoxyisobutyl-isonitrile (MIBI), and atrial pacing stress test. The % count amplitude in Tc-99m-MIBI images was calculated as [(maximal counts) - (minimal counts)]/(minimal counts) x 100. Though all patients had a low count in the septal and inferior wall in T1-201 SPECT images, there was no ischemic production of lactate during an atrial pacing stress test. Nevertheless, gated SPECT images showed attenuated septal activity during systole. In patients with LBBB, the ratios of % count amplitude at the septum to that at the lateral wall at rest (0.47 +/- 0.05, mean +/- SE) were significantly less than the controls (n = 5, 0.83 +/- 0.12, p = 0.014). In conclusion, these results suggest that abnormal T1-201 SPECT images of the septum in patients with LBBB are partially caused by impaired septal wall thickening during systole. Such an abnormal wall motion may reduce blood flow demands to the septum, resulting in reduction of coronary blood flow with little ischemia.

Imaging of hydroperoxides in a rat glomerulus stimulated by puromycin aminonucleoside

BACKGROUND

To determine the locus of the increased oxidation induced by puromycin aminonucleoside (PAN), we imaged hydroperoxides in glomeruli stimulated by PAN in vivo and in vitro.

METHODS

Dichlorofluorescein diacetate (DCFH-DA) in cells makes dichlorofluorescein, a substance that fluoresces when reacted with hydroperoxides. Fluorescence was detected using a photon detection video camera connected to a microscope. Two kinds of isolated glomeruli of Wistar rats were examined. One was the glomerulus obtained from rats on the seventh day following the injection of PAN. In this case, glomeruli were incubated in a buffer containing 5 mM DCFH-DA. Another was the glomerulus collected at 30 minutes after a large amount of DCFH-DA was intravenously injected. These glomeruli were incubated with either PAN or phorbol myristate acetate (PMA) in Krebs-Henseleite bicarbonate buffer.

RESULTS

The images from the glomeruli treated by PAN in vivo resemble pictures of a galaxy by telescope. When the glomeruli were treated by PAN in vitro, two localized points appeared in each glomerulus after 15 minutes of incubation with PAN, and after 75 minutes of incubation, the fluorescence spread throughout the glomerulus. When glomeruli were incubated with PMA, two points that gave a very strong fluorescence were observed in each glomerulus, but they did not spread throughout the glomeruli. In both experiments, glomeruli without stimulants did not fluoresce.

CONCLUSION

Increases in hydroperoxides were observed in the glomeruli from rats made nephrotic by exposure to PAN, and were also observed in glomeruli following 15 minutes of incubation with PAN in vitro.

Formation of guanidinosuccinic acid, a stable nitric oxide mimic, from argininosuccinic acid and nitric oxide-derived free radicals

Guanidinosuccinic acid (GSA) is noted for its nitric oxide (NO) mimicking actions such as vasodilatation and activation of the N-methyl-D-aspartate (NMDA) receptor. We have reported that GSA is the product of argininosuccinate (ASA) and some reactive oxygen species, mainly the hydroxyl radical. We tested for GSA synthesis in the presence of NO donors. ASA (1 mM) was incubated with NOR-2, NOC-7 or 3-morpholinosydomine hydrochloride (SIN-1) at 37 degrees C. GSA was determined by HPLC using a cationic resin for separation and phenanthrenequinone as an indicator. Neither NOR-2 or NOC-7 formed GSA. SIN-1, on the other hand, generates NO and the superoxide anion which, in turn, generated peroxynitrite which was then converted to the hydroxyl radical. Incubation of ASA with SIN-1 leads, via this route, to GSA. When ASA was incubated with 1 mM SIN-1, the amount of GSA produced depended on the incubation time and the concentration of ASA. Among the tested SIN-1 concentrations, from 0.5 to 5 mM, GSA synthesis was maximum at 0.5 mM and decreased with increasing concentrations of SIN-1. Carboxy-PTIO, a NO scavenger, completely inhibited GSA synthesis. SOD, a superoxide scavenger, decreased GSA synthesis by 20%, and catalase inhibited GSA synthesis only by 12%; DMSO, a hydroxyl radical scavenger completely inhibited GSA synthesis in the presence of SIN-1. These data suggest that the hydroxyl radical derived from a combination of NO and the superoxide anion generates GSA, a stable NO mimic. Meanwhile, synthesis of GSA by NO produces reactive oxygen and activates the NMDA receptor that generates NO from GSA, suggesting a positive feed back mechanism.

S-nitrosothiols are stored by platelets and released during platelet-neutrophil interactions

Interaction between platelets and neutrophils is important in vascular injury. We have investigated the storage and release of nitric oxide (NO) by platelets interacting with neutrophils. Shear-activated platelets were added to neutrophils in suspension and both superoxide and peroxynitrite formations monitored by lucigenin- and luminol-enhanced chemiluminescence. In addition, intraplatelet S-nitrosothiols were measured by dichlorofluorescein fluorescence following displacement of NO by mercuric chloride. Addition of activated platelets to neutrophils caused free radical production and platelet-neutrophil rosette formation. Pretreatment of platelets with 20 microM S-nitrosoglutathione changed the balance between luminol and lucigenin chemiluminescence in favor of luminol, whereas S-nitrosoglutathione in platelet-free plasma did not produce these changes. This pattern was also observed both following inhibition of neutrophil NO synthase and in a neutrophil-free superoxide-generating system. Inhibition of platelet NO synthase decreased luminol and increased lucigenin chemiluminescence. These effects were reversed by L-arginine. Platelet activation increased intraplatelet S-nitrosothiols from 1.93+/-0.19 (mean +/- SD) to 4.9+/-1.10 x 10(-18) mol/platelet (P < 0.01); this increase halved following NO synthase inhibition, but was enhanced by approximately 220% following incubation with S-nitrosoglutathione. These results show that during shear stress platelets store S-nitrosothiols, which can be derived either endogenously from NO synthesis or exogenously by sequestration of S-nitrosoglutathione. Release of stored NO during platelet-neutrophil interaction alters the interaction of NO with superoxide and could modulate vascular inflammation.

Abrasion of human enamel by brushing with a commercial dentifrice containing hydroxyapatite crystals in vitro

Automatic toothbrushing with a commercial dentifrice containing hydroxyapatite (HAP) crystals was performed on the tangential polished surfaces of sound human enamel, mainly consisting of biological apatite similar to HAP, for 10 min in vitro. The X-ray diffraction peaks of HAP, brushite (DCPD), and monetite (DCP) crystals were detected from the dentifrice. After brushing, the enamel surfaces were observed with a scanning electron and a confocal scanning laser microscope. The brushing caused larger abrasive loss and more remarkable roughness of the enamel surfaces following the broad traces of brush bristles and the exposure of prism structures than brushing with a dentifrice containing only DCPD, which we previously reported. We claim that the fine granular-shaped HAP crystals of the dentifrice indicated as an active ingredient for preventing enamel caries possess stronger abrasivity of sound enamel than the DCPD and DCP as abrasives on account of their Mohs hardness values rather than sizes and shapes. The HAP crystals of dentifrices may not occlude the small defects of early caries enamel, but erode them more strongly as an abrasive than the other abrasives.

[Outpatient chemotherapy with weekly high-dose infusional 5-fluorouracil (weekly HD-FU) in advanced gastrointestinal cancer]

This study was designed to evaluate the efficacy, toxicity, and quality of life (QOL) of outpatient chemotherapy with weekly HD-FU in advanced gastrointestinal cancer. Treatment consisted of weekly 24-h infusion of 5-FU 2,600 mg/m2, 5-FU was administered using the Groshong catheter and the Baxter infusor LV 5 (5 ml/hr). Eight patients (pts) with advanced gastrointestinal cancer were treated 64 times (mean 8.0 times), and 21 pts were treated 168 times (mean 8.0 times) with adjuvant chemotherapy. Grade 3 or 4 toxicities were not observed. Catheter occlusions and balloon rupture were observed in 1 case each. Responses were PR 2 and NC 6. Mean times to progression were 2.0 and 3.5 months, respectively. Mean scores of QOL were: 70.5 +/- 8.2 before treatment, 78.0 +/- 13.0 after 3 weeks, 79.8 +/- 7.9 after 5 weeks, and 75.8 +/- 11.3 after treatment completion. In adjuvant cases, these scores were 80.6 +/- 11.4, 83.1 +/- 10.7, 85.1 +/- 11.5, and 91.8 +/- 6.9, respectively. In conclusion, a schedule of 5-FU is feasible for outpatient chemotherapy in advanced gastrointestinal cancer.

[Clinical application of FdUrd to meningeal dissemination of malignant tumors]

A clinical trial of intrathecal chemotherapy with FdUrd was performed in sixteen patients with meningeal dissemination of malignant tumors. Twelve of the sixteen patients responded to intrathecal FdUrd chemotherapy (1-5 micrograms/dose) through an Ommaya reservoir placed in the lateral ventricle: complete response, 2; partial response, 10; progressive disease, 4. Only slight nausea was observed in two patients and dull headache in one patient. No other systemic side effects such as myelosuppression or liver dysfunction were observed in any patients. Moreover, no delayed side effects such as marked brain atrophy or leukoencephalopathy developed during the course of this intrathecal chemotherapy despite over thirty consecutive intrathecal administrations. In conclusion, intrathecal FdUrd proved to be safe and effective for the treatment of meningeal dissemination of malignant tumors.

[Intraarterial chemotherapy using a combination of etoposide and cisplatin for recurrent malignant lymphoma]

Superselective intraarterial infusion of etoposide and cisplatin was performed in 2 patients with recurrent malignant lymphoma which had progressed after operation, radiotherapy and chemotherapy with various anticancer agents. The tip of a microcatheter (Tracker-18) was placed in the left posterior cerebral artery in the first patient with the recurrent tumor located in the left occipital lobe and at the basilar top in the second patient with the recurrent tumor extending from the right thalamus to the pons. Etoposide (60 mg) and Cisplatin (60 mg) were each infused for 1 hour safely with a combination of intermittent infusion of nicardipine and papaverine chloride. The tumor disappeared completely after 2 courses of intraarterial chemotherapy in the first patient and after 1 course in the second patient. Intraarterial chemotherapy using a combination of etoposide and cisplatin was performed safely and showed good results.

Estimation of shunt flow in coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin

The shunt flow from the coronary artery to pulmonary arteries was evaluated in 6 patients with coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin. In 2 patients, whose degree of visualization of pulmonary arteries by coronary angiography was relatively high, lung perfusion scintigrams demonstrated the defects at the distal of coronary-pulmonary fistulas.

[Complications after treatment of acute coronary syndrome]

The rupture of the unstable plaque and the thrombus formation caused the occlusion of the coronary artery and followed myocardial ischemia and/or myocardial necrosis, then resulted in clinical worse outcome. The reopen of the occluded artery is the most important things for the treatment of acute coronary syndrome, and there are usually two established ways to open the occluded artery. Thrombolysis and angioplasty are already established ways to reopen, however has some complications, that is, failure to reopen, reocclusion, and bleeding. Angioscopic observations reveal the mechanism underlying these complications and suggest that platelet rich white thrombus formation continues until a month after the onset and unstable yellow plaques exist until 18 months after the onset. The most problems for the treatment in today are the unaware of the mechanism of the occlusion. If the thrombus is the major mechanism for the occlusion, thrombolytic therapy must be chosen. If the plaque is the major occlusive mechanism, the angioplasty must be chosen. To reveal the mechanisms underlying the coronary artery occlusion, we will have to use the angioscope instead of coronary angiography. After we will be able to clarify the occlusive mechanism by angioscope, we will reduce the dosage of thrombolytic agents and resulted in the decrement of bleeding complications and reopen the coronary artery effectively without complications.

Histological study of the healing process of the attachment site of rat masseter muscle following injury

The masseter muscle functions by attaching itself to the mandible. Thus, it is important to study the relationship between the masseter muscle and mandible to clarify the complex movement of the jaw. In this study, the chronological changes in the attachment site of the masseter muscle to the mandible following injury were observed in rats. These findings suggest that, in order for the masseter muscle to recover after injury, the tendinous fibers must be repaired, so that the entire muscle can be protected and recover functionality to some degree.

Remodeling of in-stent neointima, which became thinner and transparent over 3 years: serial angiographic and angioscopic follow-up

BACKGROUND

Recently, it has been reported that the luminal diameter shows phasic changes after stenting: the progression of luminal narrowing followed by its regression. To elucidate the mechanisms involved in the phasic changes in luminal diameter after stenting, we examined the changes in neointimal thickness and the appearance of neointima by a series of angiographic and angioscopic observations for 3 years after stent implantation.

METHODS AND RESULTS

In 12 patients who received a Wiktor coronary stent, serial angiographic and angioscopic examinations were performed immediately, 2 to 4 weeks, 3 months, 6 months, and 3 years after the stenting without repetition of angioplasty. Neointimal thickness was determined by angiography as the difference between stent and luminal diameters. The angioscopic appearance of neointima over the stent was classified as transparent or nontransparent according to the visibility of the majority of the stent. Neointimal thickness increased significantly at 3 months (0.75+/-0.32 mm) without further changes at 6 months (0.74+/-0.32 mm). Thereafter, however, it decreased significantly over 3 years (0.51+/-0.26 mm). The angioscopic appearance was classified as transparent in 8 patients (100) immediately after stenting, 6 patients (100%) at 2 to 4 weeks, 2 patients (17%) at 3 months, 2 patients (20%) at 6 months, and 7 patients (58%) at 3 years.

CONCLUSIONS

The neointima became thick and nontransparent until 6 months and then became thin and transparent by 3 years. We conclude that neointimal remodeling exists after stenting and plays a major role in the alteration of coronary luminal diameter after stenting.

Clinical application of power Doppler imaging to visualize coronary arteries in human beings

Supplementation of angiographic information during bypass procedures is an attractive goal for the echocardiographic researcher. Compared with color flow mapping, power Doppler imaging is superior in terms of identifying small vessels and noise suppression because of the use of Doppler signal strength for imaging. Although power Doppler imaging does not provide information about flow velocity or its direction, it does show detailed vessel flow in a static organ. Our study was designed to obtain angiographic images of the coronary artery by the use of power Doppler imaging in 31 patients during open heart surgery. During cold cardioplegic infusion, the epicardial coronary artery and the coronary artery within myocardium, such as the septal perforator, could be well visualized by power Doppler imaging. There was good correlation between the diameters of coronary arteries measured from power Doppler imaging and those from quantitative coronary angiography (r = 0.964, p < 0.0001). We obtained clear and accurate images of the coronary artery by using power Doppler imaging during cardiac standstill. These images might provide meaningful supplemental information to the operator, such as confirming the target coronary artery during the cardioplegia and choosing the appropriate arterial portion for a bypass operation.

[A case of glomerulonephritis with singular high titer of anticardiolipin antibody]

We report here a case of severe membranoproliferative glomerulonephritis with a singular high titer of anticardiolipin antibody (aCL). A 19-year-old Japanese female was admitted to Tsukuba Gakuen Hospital after complaining of general edema for 5 months. She had no past history of thrombosis, thrombocytopenia, or spontaneous abortion. Laboratory findings revealed that she had nephrotic syndrome and moderate renal dysfunction. Immunological test showed a high titer of aCL with a high-normal limit of antinuclear antibody, negativity for anti-beta(2) glycoprotein I antibody and negativity for anti-DNA antibody. In the renal biopsy tissue, most glomeruli showed global sclerosis and the remaining glomeruli revealed membranoproliferative change with crescent formation. Steroid therapy with warfarin and dipyridamole was effective and her renal function improved gradually. This case lacked the typical symptoms of primary antiphospholipid syndrome and did not satisfy the criteria of SLE. In spite of these findings, the singular high titer of aCL with membranoproliferative glomerulonephritis characterized this case.

Spherulitic brushite stone in the dental pulp of a cow

Pulp stones of human teeth usually contain biological apatite. In the dental pulp of a cow, aged 12 years, we observed spherulitic pulp stones, up to approximately 200 microns in diameter, consisting of radially arranged crystals with several kinds of light microscopy and scanning electron microscopy including the secondary electron and the backscattered electron signals. The crystals extending fan-like towards the periphery showed a rectangular shape, and they had subunits of elongated crystallites and fine slits of NaOCl-dissolved substances, probably including organic matter and amorphous mineral. By using energy-dispersive X-ray microanalysis, large amounts of Ca and P, and trace elements of Na, Mg, Cl, and Fe were detected from the stones. The calcium phosphate crystals were identified as biological brushite by shape, Ca/ P molar ratio, and electron diffraction pattern. Core regions of the stones containing granular structures, probably erythrocytes, were always present in blood vessels, and rectangular crystals frequently penetrated the vessel walls. Under the decalcified sections, the nidi were completely or incompletely dissolved, but the peripheries showed a radial arrangement of erythrocytes. Thus, the nidi may be thrombus or necrotic blood cells including erythrocytes. Such calcospherulites in the dental pulp of a cow were similar to the spherulitic pulp stones in human deciduous teeth reported previously, however, their nidi were present in different regions.

Different mechanisms of ischemic adaptation to repeated coronary occlusion in patients with and without recruitable collateral circulation

OBJECTIVES

The aim of this study was to investigate the interaction between ischemic preconditioning (IP) and collateral recruitment (CR) during ischemic adaptation in patients.

BACKGROUND

The mechanism of ischemic adaptation still remains controversial in humans.

METHODS

The clinical, electrocardiographic, hemodynamic and echocardiographic responses to three 150-s occlusions of the left anterior descending coronary artery were assessed in relation to CR in 18 patients with effort angina undergoing elective percutaneous transluminal coronary angioplasty.

RESULTS

During the first occlusion, recruitable collateral circulation (RCC) to the occluded myocardium was detected by myocardial contrast echocardiography in 6 patients (Group C) and was not seen in 12 (Group N). In Group N, all patients manifested signs of severe ischemia during each inflation. However, their symptoms and ST segment shift significantly decreased from the first to the third occlusions, suggesting the occurrence of IP. The elevation of mean pulmonary artery pressure and deterioration of anterior wall motion were comparable between the first and the third occlusions in Group N. In contrast, myocardial ischemia was significantly less marked during occlusion in Group C than in Group N, and no preconditioning effect was observed. The extent of RCC did not differ between the first and the third occlusions in each group.

CONCLUSIONS

Both IP and CR may play independent roles in ischemic adaptation in humans. With RCC, myocardial ischemia was greatly reduced. Without RCC, preconditioning clinically and electrocardiographically lessened myocardial ischemia but failed to preserve left ventricular function.

[Pregnancy and delivery in the patients with spina bifida--report of 5 cases]

BACKGROUND

Because of improvement in the management for life-threatening complications of spina bifida, quality of life in the patient has become better and pregnancy is becoming more common problem in adolescent and adult female patients. In this paper, we reported patients with spina bifida who became pregnant and delivered a baby.

METHODS

There were 6 deliveries from 5 patients. Mean patient age at the first pregnancy was 27.6 years (ranged from 26 to 32 years). Four patients had undergone surgical managements before pregnancy, of whom 1 had augmentation cystoplasty. Urological and obstetrical conditions during the pregnancy were analyzed.

RESULTS

Upper urinary tract deterioration which was transient, was observed in 3 pregnancies. Serum BUN and creatinine levels remained stable throughout pregnancy in 4 patients. Pyelonephritis complicated 3 of 6 pregnancies. Delivery was vaginal in 4 and by cesarean section in 2. There were 7 obstetrical complications, which consisted of premature labor (2), uterine inertia (2), cephalo pelvic disproportion (2) and hydramnios (1). There were no significant anomalies in the newborns of these patients.

CONCLUSION

To achieve successful pregnancy and delivery in the patient with spina bifida, careful urological and obstetrical observation for the potential complications is needed.