An attempt at electrical catheter ablation of the arrhythmogenic area in idiopathic ventricular fibrillation.
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Adolescent↗
Biomedical subjects
M Tamura
Publications and source records attributed to M Tamura.
Mediastinitis caused by odontogenic infection associated with adult respiratory distress syndrome.
A case of descending mediastinitis resulting from dental infection and complicated by adult respiratory distress syndrome (ARDS) is reported. The patient had a long history of heavy drinking. His condition was so serious that he died despite some successful therapies. The cause of ARDS appeared to be aspiration pneumonia. It is extremely rare for oral and maxillofacial surgeons to encounter a patient with ARDS.
Alcoholism↗
Collagenous deposits on explanted intraocular lenses.
An immunohistochemical study of type I collagen in deposits on the surface of two intraocular lenses (IOLs) explanted from human eyes was conducted. Type I collagen-immunoreactive proteinaceous deposits with cells were found around the haptics of an iris-supported IOL. A few such deposits and what appeared to be macrophages were observed on the optic. A few cells (presumably macrophages and giant cells) were observed on a posterior chamber IOL, whereas proteinaceous deposits that reacted positively to the antibody were not identified. Type I collagen-immunoreactive deposits on the iris-supported IOL were thought to be the products of fibroblastic cells, originating from iris tissue, that attached directly to the haptics and helped stabilize the implant.
Aged↗
Effects of recombinant human granulocyte colony-stimulating factor on neutrophil functions in aged animals.
We have studied the effects of recombinant human granulocyte colony-stimulating factor (rG-CSF) on granulopoiesis and neutrophil functions in aged rats and aged mice. We subcutaneously injected rG-CSF or control vehicle into aged rats (22 months old and 25 months old) for 7 consecutive days, counted the peripheral neutrophils and evaluated the functions of neutrophils isolated from venous blood. The peripheral neutrophil count in aged rats tended to be increased as compared with that in young rats (11 weeks old). However, the neutrophils in aged rats exhibited a decline of superoxide anion (O2-) release and phagocytic activity as compared with young rats. The peripheral neutrophil count in aged rats was significantly increased 5-6-fold as many as the control value by rG-CSF treatment, which was accompanied by a significant enhancement of O2- release and of phagocytic activity being restored to normal levels or better. In another series of experiments, we subcutaneously injected rG-CSF or control vehicle into aged mice (24-28 months old) or young mice (8 weeks old) for 7 consecutive days, and evaluated the functions of neutrophils isolated from peritoneal cavity. The peritoneal exudate neutrophils from the aged mice exhibited a decline of phagocytic and chemotactic activity as compared with the young mice. These functions in both young and aged mice were significantly enhanced by rG-CSF-treatment, and these functions in rG-CSF-treated aged mice were restored to a level higher than the level in control young mice. These findings demonstrate that rG-CSF is capable of enhancing granulopoiesis and restoring the age-related decline of neutrophil functions.
Aging↗
Clinical experience in using a new type of nasal prong for administration of N-CPAP.
Nasal continuous positive airway pressure (N-CPAP) has been used in infants with decreased lung compliance for increasing the functional residual capacity (FRC), decreasing the work of breathing and improving the PaO2/PAO2 (arterial-alveolar PO2 ratio) without intubation. However, the currently available nasal prongs for administration of N-CPAP have presented some problems in fixation, and lesions to the nasal septum or nostrils might be induced by aggressive pressure intended to fix them. We would therefore like to report our experience in using a new type of nasal prong for administration of N-CPAP therapy. The nasal prongs we used were provided by Dr. Wung of Columbia University in New York, who first designed them, and have been used safely, effectively and without any complications.
Apnea↗
Comparison of the incidence of intracranial hemorrhage following conventional mechanical ventilation and high frequency oscillation in beagle puppies.
Controversy exists as to whether high frequency oscillation (HFO) increases the risk of intraventricular hemorrhage (IVH) compared with conventional mechanical ventilation (CMV). We compared the risk of intracranial hemorrhage after phenylephrine-induced hypertension, combined with a hypovolemic, hypotensive insult followed by rapid volume replacement in two groups of newborn beagle puppies (one group on a piston pump HFO and the other on CMV). A total of 12 beagle puppies (6 on HFO and 6 on CMV) survived the protocol. Arterial blood gas analysis and arterial blood pressures through the study were of the same magnitude in both groups. The length of time for which the puppies remained hypertensive and hypotensive also did not vary significantly between the groups. Intraventricular hemorrhages were observed in two of six CMV puppies and two of six HFO puppies. One animal in each group had a white matter hemorrhage. Subarachnoid hemorrhages were seen in 4 animals on CMV and 3 on HFO. This study indicated that HFO does not increase the risk of any kind of intracranial hemorrhage, including IVH, in beagle puppies.
Animals↗
Clinical application of exogenous surfactant and high frequency oscillation in Japan.
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Blood Gas Analysis↗
Successful radiofrequency current catheter ablation of sustained ventricular tachycardia.
We performed radiofrequency current catheter ablation in two patients with nonischemic sustained ventricular tachycardia (VT). In one patient, two morphologically distinct VTs were induced by electrical stimulation. One showed right bundle branch block pattern and the other left bundle branch block pattern. The earliest site of activation during each VT was determined at the septum of the right ventricle. However, these two sites were close to the His-bundle electrogram recording area. In the other patient, a VT with a left bundle branch block pattern occurred spontaneously after the administration of isoproterenol. The earliest site of activation during VT was determined at the outflow tract of the right ventricle. During tachycardia, radiofrequency current ablation (40 W x 30 sec) was delivered to the earliest site of activation. A few seconds after fulguration, each VT was terminated and additional radiofrequency currents were given near these sites. After the ablation, VT could not be induced by the electrical stimulations, nor did it recur. No side effects were observed and the atrioventricular conduction remained intact. We feel that nonischemic VTs could possibly be treated by using radiofrequency current catheter ablation.
Aged↗
Frequency and output-dependent change in conduction over slow pathways in a patient with sustained ventricular tachycardia unrelated to coronary artery disease.
In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."
Bundle-Branch Block↗
Lipopolysaccharides of Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis induce interleukin-8 gene expression in human gingival fibroblast cultures.
Lipopolysaccharides (LPS) prepared from Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis by hot phenol-water extraction induced interleukin-8 (IL-8) mRNA in normal human gingival fibroblast cultures, as demonstrated by Northern (RNA) blot analysis. IL-8 mRNA levels began to increase after a 2-h exposure, reached a maximum after 12 h, and then dropped to the unstimulated level at 48 h. IL-8 mRNA levels were also enhanced in a dose-dependent manner. By contrast, LPS specimens from various Salmonella species with S and R chemotypes and bacterial [corrected] and synthetic lipid A preparations did not increase IL-8 mRNA levels in fibroblasts. Although recombinant human IL-1 alpha induced IL-8 mRNA expression in fibroblast cultures, an antiserum to recombinant human IL-1 alpha did not decrease the IL-8 mRNA accumulation induced by B. intermedius LPS. Fibroblasts primed with natural human gamma interferon (IFN-gamma) expressed higher IL-8 mRNA levels upon stimulation with B. intermedius LPS, but not with Salmonella LPS, compared with nontreated cells. Natural human IFN-beta exhibited a similar priming effect on the fibroblasts, and antiserum to IFN-beta added to the cultures together with B. intermedius LPS decreased the IL-8 mRNA levels. Therefore, endogenous IFN-beta enhanced IL-8 mRNA production in response to B. intermedius LPS in fibroblasts.
Bacteroides↗
Application of ubiquinone systems and electrophoretic comparison of enzymes to identification of clinical isolates of Aspergillus fumigatus and several other species of Aspergillus.
The ubiquinone systems and electrophoretic comparison of enzymes were used to determine the relatedness among 64 isolates of seven Aspergillus spp. These were 31 clinical and 3 nonclinical isolates of Aspergillus fumigatus Fres., 2 isolates of A. nidulellus Samson & W. Gams, 8 isolates of A. terreus Thom, 4 isolates of A. flavus Link, 1 isolate of A. oryzae (Ahlburg) Cohn, 14 isolates of A. niger van Tieghem, and 1 isolate of A. japonicus Saito. The enzymes glucose 6-phosphate dehydrogenase, lactate dehydrogenase, glutamate dehydrogenase, fumarase, and malate dehydrogenase were examined. The relative mobilities were analyzed numerically. The results were presented as a dendrogram. Isolates from clinical and nonclinical sources within the same species had identical ubiquinone systems and identical or very similar enzyme patterns. In the dendrogram, 64 of the tested isolates were separated into seven major clusters at a 60% similarity level. Each major cluster corresponds to a single species. On the dendrogram, A. fumigatus isolates showed homogeneity, whereas A. niger isolates showed relative heterogeneity; in particular, A. niger MF-24 and the other A. niger isolates were distantly linked to each other. All A. fumigatus isolates had the Q-10 ubiquinone system and formed a single major cluster at a similarity level of 73% or greater. Glucose 6-phosphate dehydrogenase and glutamate dehydrogenase were key enzymes for differentiating all clinical and nonclinical isolates of A. fumigatus from the other Aspergillus spp. Ubiquinone systems and enzyme patterns appear to be objective and useful indicators for use in the precise identification of clinical isolates of Aspergillus spp.
Aspergillus↗
Incidence and mechanism of interruption of reentrant ventricular tachycardia with rapid ventricular pacing.
BACKGROUND: Information concerning the electrophysiological characteristics of the reentrant circuit is still limited. To understand the incidence and mechanism of pacing-induced interruption of ventricular tachycardia (VT), rapid pacing was performed to entrain VT, and the local electrogram at the VT origin and the surface electrocardiogram were analyzed. METHODS AND RESULTS: Among 25 patients, evidence of transient entrainment was confirmed in 20 patients, but the critical paced cycle length at which VT was interrupted was obtained in 13 patients when the paced cycle length was decreased in steps of 10 msec. During pacing at the critical cycle length (defined as block cycle length), changes in the local electrogram at VT origin were confirmed in all of the 13 patients; that is, 1) a change in morphology and 2) a change in the timing of activation: a sudden shortening in the stimulus to local electrogram time (third entrainment criterion by Waldo). The two changes mean that the exit is activated from a different direction (retrograde capture) because of an orthodromic block in the slow conduction zone. The QRS complex in the surface electrocardiogram showed a change in configuration from the fusion complex to the fully paced one at the same time when the exit was captured antidromically. CONCLUSIONS: Based on our observations in these patients, ventricular tachycardia interruption is very often associated with orthodromic block in the reentrant circuit at a critical cycle length of rapid pacing.
Adolescent↗
NG-methyl-L-arginine, an inhibitor of L-arginine-derived nitric oxide synthesis, stimulates renal sympathetic nerve activity in vivo. A role for nitric oxide in the central regulation of sympathetic tone?
Continuous production of endothelium-derived nitric oxide (NO) in peripheral vessels has been shown to modulate vascular resistance and blood pressure. NO is also formed in the brain upon activation of glutamate receptors, which are thought to mediate central autonomic reflexes. In the present study we assessed whether NO plays a role in central autonomic regulation. For this, we have investigated the effects of NG-methyl-L-arginine (NMA), a selective inhibitor of NO synthesis from L-arginine, on sympathetic renal nerve activity (RNA), blood pressure, and heart rate in the anesthetized rat. NMA elicited a dose-dependent sustained increase in blood pressure (approximately 20 and 30 mm Hg, 5 minutes after 10 and 50 mumol/kg i.v., respectively). Heart rate and RNA decreased transiently (15 beats per minute and 40%, respectively); RNA subsequently increased (100%) while blood pressure remained elevated. Baroreceptor deafferentation markedly altered these responses to NMA; the transient decreases in heart rate and RNA were abolished, whereas the increases in RNA and blood pressure were significantly potentiated. After spinal C-1-C-2 transection, there was no increase in RNA, and blood pressure increased to a smaller extent. L-Arginine blocked the NMA-induced increases in blood pressure and RNA. Thus, in addition to modulating vascular resistance by a peripheral action, NO may also play a role in the central regulation of sympathetic tone.
Animals↗
Protective effects of a PGI2 analogue OP-2507 on hemorrhagic shock in rats--with an evaluation of the metabolic recovery using near-infrared optical monitoring.
The protective effects of the PGI2 analogue, OP-2507 against hypoxic tissue injury were investigated in a 60-70 min acute hemorrhagic shock model in 29 rats. To assess the metabolic recovery of mitochondria after tissue injury induced by hemorrhagic hypotension with a mean arterial pressure of 30 mmHg, we have non-invasively monitored changes in the brain tissue parameters of cyt. aa3 redox state, blood oxygenation and relative blood volume by spectrophotometry through the closed skull and intact skin. Pretreatment with 0.1 mg/Kg s.c. of OP-2507 at 30-40 min before induction of shock was performed on 14 rats (OP-treated group). The remaining 15 rats were used as a control (control group). There was a consistent prolongation of survival time and a significant improvement in survival rate after reinfusion of the shed blood in the OP-treated group. In this group there was a rapid and complete reoxidation of cyt. aa3 with a mean overshoot of 9 +/- 5.5% above the baseline value after reinfusion. On the other hand, in the control group the extent of reoxidation was significantly lower, with a minimal 11 +/- 3.2% below the base line. In order to evaluate the mechanisms involved 10 mg of NaCN i.v. was administered to the living rats at 60-70 min after reinfusion of the blood in both groups. In the OP-treated group, brain Hb saturation increased up to 20% above the pre-cyanide infusion level. However in the control group there was a non-significant increase in the Hb oxygenation level. These observation indicate that in the OP-treated group oxygen consumption by mitochondria is significantly higher than that in the control group. Thus, enhanced oxygen utilization could lead to the active restoration of injured tissue by promoting oxidative phosphorylation. Under these experimental conditions the oxidative response of cyt. aa3 is concluded to correlate closely with the prognosis of shock animals in both groups. These results indicate the potential usefulness of OP-2507 in protecting the brain and other organs from oxygen insufficiency as a result of tissue ischemia and anoxia.
Animals↗
Cisplatin-induced emesis in Suncus murinus.
Emetic responses to cisplatin and participation of vagal innervation in emesis were studied in suncus. Intraperitoneal and intravenous administration of cisplatin caused dose-dependent emesis. ED50 values, latencies and frequencies were not significantly different between the two administrations. Cis-diaqodiammineplatinum (DAP), an active metabolite of cisplatin, also induced emesis, but with significantly shorter latency. Vagotomy completely abolished both types of vomiting. These results suggest that cisplatin is metabolized to DAP that subsequently causes emesis through stimulation of the vagus afferent.
Animals↗
Clinical features of BOOP in Japan.
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Adult↗
High prevalence of coronary artery spasm in survivors of cardiac arrest with no apparent heart disease.
The pathogenesis of cardiac arrest in the absence of any apparent heart disease remains unclear. Based on the hypothesis that coronary spasm may be a cause of cardiac arrest in the absence of apparent heart disease, ergonovine testing and/or electrophysiologic studies (EPS) were performed to evaluate the cause of cardiac arrest. Fourteen patients resuscitated from cardiac arrest had no apparent heart disease. A spontaneous episode of angina with ST-segment elevation occurred in 4 patients while under observation. Ergonovine testing was performed in 9 patients, and coronary spasm was induced in 5. EPS were performed in 8 patients, including 3 patients with coronary spasm. No electrophysiologic abnormalities were found in the 3 patients with coronary spasm. Ventricular fibrillation was induced by programmed ventricular stimulation in 2 patients with documented ventricular fibrillation at the time of resuscitation. All but one of the patients with coronary spasm had chest pain preceding cardiac arrest or at least a history of chest pain at rest, while 4 of 5 patients without coronary spasm had no prodromal symptoms. Patients with coronary spasm had a good prognosis when treated with a Ca-antagonist and/or long-acting nitrate. In conclusion, coronary spasm is the most frequent cause of cardiac arrest in cardiac arrest survivors with no apparent heart disease. Ergonovine testing should be performed to evaluate the cause of cardiac arrest when patients have no apparent heart disease.
Cardiac Pacing, Artificial↗
Intraventricular concealed double tachycardia: a case report.
An electrophysiologic study was performed on a patient with ischemic sustained ventricular tachycardia (VT). During pacing at the right ventricular apex, ventricular double potential was recorded at the left ventricular apex. Sustained VT was induced by double extra stimuli from the right ventricular apex. Three types of VTs with different QRS morphologies were observed, and each VT was changeable to other types. The interval between one of the two potentials and the surface QRS was constant during all VTs, but the other potential showed dissociation from the surface QRS. During this dissociation, an intrinsic rhythm of the potential was sometimes shorter than the cycle length of the VT. The mechanism of a block between the VT and a bystander could hardly explain these electrophysiologic findings. Concealed double ventricular tachycardia was considered to be the likely mechanism.
Aged↗