[Autopsy case of malignant melanoma of the lower esophagus].
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Adult↗
Biomedical subjects
S Miyajima
Publications and source records attributed to S Miyajima.
Orthodromic capture of the atrial electrogram during transient entrainment of atrioventricular nodal reentrant tachycardia.
BACKGROUND: The reentry circuit of atrioventricular nodal reentrant tachycardia (AVNRT) has not been fully demonstrated. We hypothesized that if an upper common pathway was present, the atrial electrogram could not be captured orthodromically during transient entrainment of AVNRT by rapid atrial pacing. Based on this hypothesis, the presence of an upper common pathway was investigated. METHODS AND RESULTS: The atrial electrogram at the recording site of the His bundle potential was identified during induced AVNRT in 9 patients. To entrain AVNRT transiently, rapid pacing from the high right atrium and coronary sinus was applied at a cycle length 10 milliseconds shorter than that of AVNRT and repeated after a decrement of the paced cycle length in steps of 5 milliseconds until AVNRT was interrupted. In 5 of 7 patients, orthodromic capture of the atrial electrogram at the recording site of the His bundle potential was observed during transient entrainment of AVNRT by coronary sinus pacing, ie, the first postpacing interval of the atrial electrogram at the recording site of the His bundle potential was the same as the paced cycle length. In these 5 patients, the mean minimum paced cycle length capable of orthodromic atrial capture was 349 milliseconds, and the mean difference from the cycle length of AVNRT was only 16 milliseconds. During transient entrainment of AVNRT by high right atrial pacing, the atrial electrogram could not be captured orthodromically. CONCLUSIONS: Observation of orthodromic capture of the atrial electrogram at the recording site of the His bundle potential by coronary sinus pacing ruled out the presence of an upper common pathway in AVNRT, and the concept that perinodal atrial tissue is involved in the reentry circuit of AVNRT was supported.
Atrial Function↗
Immature teratoma of the uterine fundus.
An exceedingly rare case of extragonadal immature teratoma, which occurred primarily in the uterus, is described. The tumor developed into the pelvic cavity from the uterine fundus and consisted of ectodermal, mesodermal and endodermal derivatives. There were also significant amounts of immature elements; immature neuroepithelium with brisk mitotic activity, immature mesenchymal tissue, immature cartilage, immature striated muscle and immature hepatic tissue. Histologically, it was classified as a grade 3 immature teratoma. Treatment consisted of total simple hysterectomy followed by 2 courses of combination chemotherapy with vincristine, actinomycin D and cyclophosphamide (VAC). The patient was well and without evidence of recurrence at 5 years post-operatively.
Adult↗
Scanning electron microscopic observations of the arachnoid granulations in monkeys with cerebrospinal fluid hypotension.
The changes in arachnoid granulations following the depletion of cerebrospinal fluid (CSF) were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the normal tissue, the arachnoid granulations located at the inner walls of the superior sagittal sinus and the straight sinus had bulging protrusions of various sizes, as viewed with the SEM. With TEM, the outermost cells covering the surface of the arachnoid granulations had "giant vacuoles" in the cytoplasm. With CSF hypotension, the arachnoid granulations were smaller in size and the outermost layer of cells were thinner. The vacuoles in the outer layer were not developed. In the apical region of the individual arachnoid granulations with CSF hypotension, the arachnoid cells were densely clustered under the endothelial cells. With recovery to normal CSF pressure, the arachnoid cells appeared to protrude between the endothelial cells covering the apical portion of the arachnoid granulation.
Animals↗
Partial release of aminopeptidase N from larval midgut cell membranes of the silkworm, Bombyx mori, by phosphatidylinositol-specific phospholipase C.
1. The membrane anchor of aminopeptidase N associated with larval midgut cell membranes of the silkworm, Bombyx mori, was investigated by using phosphatidylinositol-specific phospholipase C (PIPLC) and proteases. 2. Aminopeptidase N, which was virtually all localized in the brush border membrane, was solubilized by PIPLC but not by papain or trypsin. 3. Detergent-solubilized amphiphilic aminopeptidase N was converted into a hydrophilic form by PIPLC but not by papain. 4. Either of these effects of PIPLC on aminopeptidase N was maximally 40%. 5. These results suggest that in larval midgut cells of the silkworm, B. mori, at least 40% aminopeptidase N is anchored in the brush border membrane via glycosyl-phosphatidylinositol.
Aminopeptidases↗
Protective activity of adult T cell leukemia-derived factor (ADF) against tumor necrosis factor-dependent cytotoxicity on U937 cells.
Adult T cell leukemia-derived factor (ADF) is a human homologue of thioredoxin with many biologic functions including IL-2R induction, growth promotion, thiol-dependent reducing activity, and radical scavenging activity. The regulatory effect of ADF on the cytotoxic activity of TNF was examined by using a human histiocytic lymphoma cell line, U937. When U937 cells were preincubated with recombinant ADF (rADF) (0.1-100 micrograms/ml) at 37 degrees C for 30 min, TNF-dependent cytotoxicity on U937 cells was markedly inhibited. This inhibitory effect was as high as 95% in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (rADF 100 micrograms/ml) and 85% in the 51Cr-releasing assay (rADF 10 micrograms/ml). After pretreatment of U937 cells with IFN-gamma to augment the sensitivity to TNF, an inhibitory effect of rADF was also found. When U937 cells were washed after preincubation with rADF, resistance to TNF-dependent cytotoxicity was still observed, indicating that rADF inhibited the sensitivity of U937 to TNF-dependent cytotoxicity rather than modifying TNF molecules. Scatchard analysis of TNF receptors on U937 cells using 125I-TNF showed that rADF modulated neither the density nor the affinity of the cell membrane significantly. rADF also reduced the cytotoxicity induced by anti-Fas IgM mAb which shows cytotoxicity quite similar to TNF. rADF (10 micrograms/ml) reduced 90% of the cytotoxicity by anti-Fas IgM mAb, without a detectable change either in Fas Ag expression (MFI 58.1 vs 53.3) or in the degradation of anti-Fas IgM mAb as determined by flow cytometric analysis. These findings indicated that the rADF-induced resistance to the cytotoxic effect of TNF and anti-Fas mAb was not related to the modulation of the TNF receptor or Fas Ag.
Antigens, Surface↗
Proarrhythmic effects of antiarrhythmic drugs assessed by electrophysiologic study in recurrent sustained ventricular tachycardia.
Proarrhythmic responses were evaluated in repeated electrophysiologic studies (EPS) in 27 patients with inducible ventricular tachycardia (VT). Class Ia drugs were administered to 23, Ib to 6, Ic to 4, III to 5 and IV to 9 patients. The mean age was 53 years, and 18 patients had structural heart diseases. Pleomorphism was observed in 11 patients. In 4 patients (15%), the VT cycle length (CL) shortened by 50 ms or more in EPS during the administration of antiarrhythmic drugs. VT was inducible by a less aggressive induction mode than the control study in 9 patients (33%). In 4 patients (15%), the induced VT changed to the incessant form, and the other 2 patients (7%) required DC shocks due to hemodynamic deterioration. Patients with pleomorphic VT and/or structural heart diseases seemed to develop proarrhythmia more frequently. In total, some proarrhythmic response was observed in 13 (48%) of the 27 patients. Therefore, it should be kept in mind that proarrhythmic effects are frequently observed during antiarrhythmic therapy in patients with sustained VT. The action of the drugs on the slow conduction zone may vary, which may provide a basis for the development of proarrhythmia.
Anti-Arrhythmia Agents↗
Flagellum abnormalities of spermatozoa in seminiferous tubules after a short term vasectomy.
Electron microscopic observation was performed to examine whether spermiogenesis in the hamster might be affected by a short term vasectomy. When viewed by light microscopy, spermiogenesis was temporarily inhibited at 2 weeks, though to a limited extent among individuals, and had apparently recovered to the control level at 4 and 8 weeks after vasectomy in all hamsters. It was revealed at the electron microscopic level that mature spermatozoa with an abnormal flagellum were intermingled among numerous normal spermatozoa. The flagellum of the mature spermatozoa was composed of four different components: a mitochondrial sheath, outer dense fiber, fibrous sheath and axoneme. Abnormalities of the mitochondrial sheath were of three types: its discontinuity, displasia and deformation. The appearance of these abnormalities increased with the time after vasectomy and finally reached 52% as the highest value at 8 weeks. Additional noteworthy findings were the bisectioning of the outer dense fibers 2, 4 and 7, the fusion of two or three fibers, and the partial deletion of the fibrous sheath. These defects were characteristic in the vasectomized hamsters. Possible correlating microenvironmental factors are discussed as to how these abnormalities of the four flagellar components occur in the vasectomized hamsters.
Animals↗
Ultrastructure of the perineurial cell of the sciatic nerve in rats--a transmission and scanning electron microscopic study.
The perineurial cells of the sciatic nerve of mature albino rats were investigated by using light microscope (LM), transmission electron microscope (TEM) and scanning electron microscope (SEM). The perineurium of the sciatic nerve was composed of several lamellae of thin perineurial cells which were held together by the zonula occludens and also by the zonula adherens. The TEM view of the perineurium revealed that the plasmalemma of the perineurial cells presented numerous caveolae similar to those described in the endothelial cells of blood capillaries. By SEM, the perineurial cells were very thin, flattened out with various shapes from rectangular to hexagonal, and arranged closely to each other in the fashion of a stone pavement around the nerve fascicles. It was possible to isolate the perineurium from the nerve and to demonstrate the cellular border of the perineurial cells by silver impregnation method. The SEM observation of the perineurial cells ascertained the figure of the cells which were seen in the silver-impregnated specimen under LM. The present authors have interest in the fact that shape and arrangement of the perineurial cells of spinal nerves resemble closely those of the myoid cells in the limiting lamina of the seminiferous tubules of the mammalian testes. The meaning and significance of the similarity between these two types of cells was discussed.
Animals↗
Two-dimensional metallic hydrogen in the potassium-hydrogen-graphite ternary intercalation compound.
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Journal Article↗
Ventricular tachycardia with two possible exits from one re-entrant circuit.
A case of sustained ventricular tachycardia (VT) with two possible exits from one re-entrant circuit is described in this paper. The patient was a 27-year-old female who had undergone corrective surgery for tetralogy of Fallot at the age of 8, and developed VT of distinctly different QRS configurations. The exit of one VT was at the right ventricular (RV) outflow tract and the other at the RV apex as determined by endocardial and pace-mapping. Continuous and split activities were observed at the RV outflow tract during both types of VT. One VT was entrained by rapid pacings, and the causal mechanism was thought to be re-entry and common re-entrant circuit was established for two QRS configurations of VTs. A discrepancy was observed between the site of the earliest activation and the site of the pace-mapping which resulted in QRS configuration of VT of the RV apex origin. The findings in this paper should be considered when contemplating aggressive therapy such as electrical ablation.
Adult↗
[Abnormal local ventricular electrogram and its relation to induction of ventricular tachycardia in patients with hypertrophic cardiomyopathy].
To investigate the mechanism of induction of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM), we reviewed and analyzed the local ventricular electrograms (LVE) at the pacing sites in 15 patients with HCM and 52 control subjects. Each patient had a clinical history of nonsustained VT or syncope. The results were as follows: 1. Rapid and polymorphic VT was induced in six of the 15 patients with HCM and in 10 of the 52 control subjects. 2. The duration of the LVE at the pacing site was progressively prolonged as the number of extrastimuli were increased or the premature intervals were shortened. Compared with the controls, patients with HCM had longer durations of the LVE by basic drive, single extrastimulus, and by double extrastimuli: 113 +/- 31 vs 95 +/- 16 ms (p less than 0.005), 156 +/- 35 vs 109 +/- 17 ms (p less than 0.001), and 220 +/- 88 vs 133 +/- 25 ms (p less than 0.001), respectively. 3. In the HCM group, the maximum duration of the LVE by double ventricular extrastimuli was significantly longer in patients with inducible VT compared with those with non-inducible VT: 287 +/- 95 vs 183 +/- 56 ms (p less than 0.05). 4. Induction of VT in the HCM group was accompanied by the critical prolongation of the LVE at the pacing site. In two of the six patients with HCM, the LVE at the pacing site spanned the entire cardiac cycle at the time of the initiation of VT.(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiomyopathy, Hypertrophic↗
Membrane anchors of alkaline phosphatase and trehalase associated with the plasma membrane of larval midgut epithelial cells of the silkworm, Bombyx mori.
The larval midgut epithelial cell of the silkworm, Bombyx mori, has two forms of alkaline phosphatase and trehalase, soluble and membrane-bound. Alkaline phosphatase and trehalase of the latter form are found in the brush border membrane and the basolateral membrane, respectively. In this work we studied the membrane anchors of these membrane-bound enzymes. Alkaline phosphatase was solubilized by phosphatidyl-inositol-specific phospholipase C, but not by papain. Conversely, trehalase was released from the membrane by papain, but not by phosphatidylinositol-specific phospholipase C. Both enzymes were solubilized in an amphiphilic form with 0.5% Triton X-100 plus 0.5% sodium deoxycholate (pH 7.0). The detergent-solubilized alkaline phosphatase and trehalase were converted to hydrophilic form on incubation with phosphatidylinositol-specific phospholipase C and papain, respectively. The effects of papain on solubilization and conversion of trehalase were completely inhibited by leupeptin. These results suggest that, in the silkworm larvae, alkaline phosphatase is anchored in the brush-border membrane via a glycosyl-phosphatidylinositol, while trehalase is associated with the basolateral membrane through a hydrophobic segment of the polypeptide.
Alkaline Phosphatase↗
Electrophysiologic evaluation of asymptomatic patients with the Wolff-Parkinson-White pattern.
In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.
Adult↗
Augmented fragmentation of atrial activity upon premature electrical stimuli by verapamil.
The significance of fragmented activity obtained from the atrium during electrophysiologic study (EP study) was confirmed since it was always observed just at the onset of fibrillation. It was preceded by extra stimuli or atrial flutter, and the initial site of fragmentation varied from case to case. The premature-stimulus-induced widening of the atrial wave was observed in some cases who had normal size of atrium and no heart failure. The widening was augmented by administration of verapamil but not by procainamide, suggesting that for such widening or fragmented activity, slow-fiber-mediated conduction seems to be responsible. One case with intraatrial reentrant tachycardia developed fragmentation lasting for 1.0 second after verapamil. Therefore, some apparently normal atria may have a subclinical electrophysiologic abnormality that can be disclosed by premature stimulations or verapamil.
Adolescent↗
Attenuation of reactive hyperemia caused by aspirin in canine coronary artery.
Effects of intracoronary aspirin on coronary blood flow and reactive hyperemia were evaluated in closed-chest, anesthetized dogs. In 18 dogs the left circumflex coronary artery was cannulated and perfused by arterial blood at a constant pressure. Coronary blood flow was measured by an electromagnetic flowmeter. Intracoronary aspirin at doses of 5, 10, and 20 mg reduced coronary blood flow in a dose-dependent manner. Injection of aspirin at doses of 10 to 25 mg also inhibited reactive hyperemia following the coronary occlusion for fifteen seconds. The mean peak flow ratio was reduced from 2.13 +/- 0.42 to 1.75 +/- 0.35 (p less than 0.005). The increment of coronary blood flow provoked by intracoronary arachidonic acid at doses of 150 to 300 micrograms was almost entirely inhibited by the pretreatment of the coronary artery with aspirin. The authors conclude that aspirin increases coronary arterial resistance in a dose-dependent manner and also restricts the maximal dilating capacity, possibly by inhibition of prostacyclin synthesis.
Animals↗
Sustained ventricular tachycardia responsive to verapamil in patients with hypertrophic cardiomyopathy. Clinical and electrophysiological assessment of drug efficacy.
Recently, we examined 2 cases of hypertrophic cardiomyopathy (HCM) presenting with sustained ventricular tachycardia (VT). One case was a 62 year old male with midventricular hypertrophy and monomorphic sustained VT. After admission, the efficacies of procainamide, disopyramide, aprindin, flecainide, mexiletine and verapamil were evaluated by means of continuous electrocardiographic monitoring. Verapamil prevented the recurrence of sustained VT and markedly reduced the frequency and number of runs of nonsustained VT. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular apex. Intravenous verapamil at a dose of 10 mg prevented the induction of VT. The patient was discharged on verapamil and remains asymptomatic after 3 months of follow up. The other case was a 34 year old female who was a survivor of cardiac arrest. Monomorphic VT was observed on emergency admission and was converted to sinus rhythm by direct current cardioversion after resuscitation. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular outflow tract. Verapamil at a dose of 10 mg prevented the induction of VT. These 2 cases of HCM are rare in that they presented with sustained VT. It is also of interest that verapamil, which has been used conventionally in HCM, prevented VT.
Adult↗
[Association of sustained ventricular tachycardia and a mid-systolic click: a case report].
A 27-year-old woman had a history of palpitation at the age of nine. Ventricular tachycardia (VT) was detected four years ago and treatment with procainamide was started. Physical examination disclosed nothing abnormal other than an apical mid-systolic click. Electrocardiogram and chest radiograph were normal, and echocardiogram disclosed borderline mitral valve prolapse (MVP). VT was not provoked by exercise, and Holter monitorings of electrocardiogram were always within a normal limit. Angiography was normal. Electrophysiological study disclosed VT by left ventricular stimulation and the earliest activation was at the apex, VT was abolished by early stimulation from the right ventricular apex. The association of a mid-systolic click and VT was interesting in this case. When the patient had a systolic click at the outpatient clinic, VT frequently occurred within a month (six of seven times), while VT did not occur without an audible systolic click (three of four times). Although it is uncertain whether VT of this patient has any relationship to MVP or to the click, these problems remain to be solved in the future.
Adult↗