Spontaneous Termination of Reentry Ventricular Tachycardia in the Late Myocardial Infarction Period: An Experimental Study in the Dog

Forty episodes of induced ventricular tachycardia in the late myocardial infarction period (4-6 days old) were analyzed in 12 dogs in an attempt to identify the possible mechanisms for the termination of reentry tachycardia. Multiple epicardial and endocardial composite electrograms were recorded in and around the central ischemic zone of the infarction. During tachycardia, the earliest site of activation was identified in the epicardial surface of the border or normal zone immediately adjacent to the ischemic zone in 36 of the 40 episodes, suggesting efferent epicardial spread from the site of the activity. In four instances, the efferent pathways were directed to the endocardial surface. Four distinct patterns of activation sequences were observed during spontaneous termination: (a) a shift of the efferent pathways from epicardial to endocardial site (19 instances); (b) a change of the efferent pathways within the endocardium (4 instances); (c) a shift of the earliest site of activation between the left and right ventricles (9 instances); and (d) no apparent change in the epicardial efferent pathways (4 instances). In four other instances, ventricular tachycardia deteriorated into ventricular fibrillation. In patterns (a) and (c), a shift of the efferent pathways resulted in a more rapid and homogeneous activation of the border and normal zone epicardium. These changes were associated with cessation of delayed or continuous activity in the ischemic zone epicardium, resulting in termination of tachycardia.     

Role of ureteroscopic biopsy in the management of upper urinary tract malignancy

BACKGROUND: The aim of the study presented here was to examine the accuracy of ureteroscopic biopsy in the diagnosis of upper urinary tract transitional cell carcinoma (TCC) and whether nephron-sparing management (holmium YAG laser, transurethral resection or partial ureterectomy) is possible or not based on pathological diagnosis. METHODS: Forty consecutive patients underwent ureteroscopic biopsy with the use of 3-Fr cold cup forceps. Pathological diagnosis of the biopsy sample and grade or stage of surgically resected tumors were compared. In patients with grade 1 or 2 TCC diagnosed by ureteroscopic biopsy, the disease-free and survival rates determined whether nephron-sparing management was performed or not. RESULTS: There were no major complications associated with ureteroscopic biopsy. The pathological grading of the biopsy specimen was almost the same as that of the surgically resected specimen. Eighty five percent of grade 2 or 3 TCC showed muscle invasive disease. There were no significant differences in the disease-free and survival rates between the nephroureterectomy and the nephron-sparing management groups, except for grade 3 or pT3 tumors. CONCLUSION: Ureteroscopic biopsy is safe and accurate if sufficient tissue sample is obtained. Ureteroscopic biopsy should be performed in patients who require nephron-sparing management. Nephroureterectomy can be avoided if the tumor is confirmed as low-grade.     

A tumor necrosis factor (TNF) receptor fragment attenuates TNF-α- and muramyl dipeptide-induced sleep and fever in rabbits

It is hypothesized that tumour necrosis factor (TNF) is an endogenous substance involved in sleep responses occurring during bacterial infection. If this hypothesis is correct, then blocking endogenous TNF, using a TNF inhibitor, should attenuate the bacterial cell wall-derived, muramyl dipeptide (MDP)-induced sleep. To test this hypothesis, the effects of intracerebroventricular (i.c.v.) injection of a TNF inhibitor, a biologically active fragment of the soluble TNF 55 kDa receptor (TNFRF), on TNF-α- and MDP-induced sleep were determined in rabbits. I.c.v. injection of 250 ng human recombinant TNF-α- or 150 pmol MDP increased non-rapid-eye-movement sleep (NREMS), decreased rapid-eye-movement sleep (REMS), enhanced electroencephalogram slow-wave activity (SWA) during NREMS and induced fever. Pretreatment of rabbits with 25 μg of the TNFRF significantly inhibited TNF-α- and MDP-induced sleep and fever responses. Finally, intravenously (i.v.) injected MDP enhanced NREMS, suppressed REMS, enhanced SWA, and induced fever; pretreatment of animals with the TNFRF injected centrally attenuated i.v. MDP-induced sleep responses but not fever. These results suggest that the TNFRF acts as a TNF-α antagonist in vivo and support the hypothesis that MDP-induced sleep is partially mediated via brain TNF-α.     

Shortening of the hippocampal formation in first-episode schizophrenic patients

Abstract Shortening of hippocampal formation (HF) in chronic schizophrenic patients have been demonstrated in our previous study. The purpose of the present study is to test if shortening of the HF occurs in schizophrenic patients suffering their initial psychotic episode. We performed contiguous, 1 mm thick, magnetic resonance imaging scans in 20 first-episode schizophrenic patients, 21 chronic schizophrenic patients, and 25 healthy subjects. Both groups of schizophrenic patients demonstrated significant shortening of the HF compared with normal controls (first-episode schizophrenia, 5.3%; chronic schizophrenia, 8.0%). However, the HF length was not significantly different between the first-episode and chronic schizophrenic patients. No significant correlation was seen between the HF length and the duration of illness in chronic schizophrenic patients. These results suggest that the HF shortening observed in schizophrenic patients may be genetic and/or developmental in origin.     

Chemical modification of superoxide dismutase Extension of plasma half life of the enzyme through its reversible binding to the circulating albumin

Protection of organisms from oxidative stress is one of the major prerequisites for aerobic life. Since intravenously injected Cu⁺⁺/Zn⁺⁺ -type superoxide dismutase (SOD) rapidly undergoes renal glomerular filtration and appears in urine in its intact form, its clinical use as a scavenger for superoxide radicals has been highly limited. To test whether reversible interaction of SOD with plasma albumin might decrease the rate of disappearance of the enzyme from the circulation, the lysyl residues of the human erythrocyte-type enzyme were covalently linked with poly-(styrene-co-maleic acid) butyl ester (SMA) via amide linkage. Affinity chromatographic analysis by an albumin-Sepharose column revealed that the enzyme samples labeled with SMA (SMA-SOD) tightly bound to the column, while unmodified SOD was eluted in the unbound fractions. SMA-SOD bound to the column could be eluted by the buffer solution containing 0.1% sodium dodecylsulfate. In vivo analysis revealed that intravenously administered SMA-SOD circulated bound to albumin with an extremely long half-life (6 h), while unmodified SOD rapidly underwent renal glomerular filtration with a plasma half-life of 4min. Thus, SMA-SOD may effectively dismutate superoxide radicals in the circulation.     

Metastatic Bone Tumors: Diagnosis and Treatment

Seventy-four cases of metastatic bone tumors were reviewed inorder to study the actual problems concerning their diagnosisand treatment. Sixty-five of the 74 tumors were carcinoma metastasesand the remaining nine were other malignancies. Diagnosis: In our study, as has often been reported elsewhere,there was a high incidence of metastasis of lung and breastcancer (27% and 9%, respectively). In all patients in this series,the existence of bone metastasis itself was shown by plain radiogramsat the time of their admission. In 51 patients, primary siteswere identified by clinical records and/or various clinicalexaminations. Autopsy revealed additional seven primary sites. Treatment: Limb surgery which directly intends a resection ofthe metastatic lesion generally provided good palliation and,on occasion, relatively long survival. Of the seven patientswhose bone lesions were enthusiastically resected, three survivedfor 15, 27 and 36 months postoperatively and one has survivedup to the present (18 months). On the other hand, laminectomy and other procedures of vertebralsurgery which do not directly intend a resection did not givegood results in either quad vitam vol functionem. Twenty of21 patients died within a relatively short time (1 to 13 months,average 3.6 months) without any functional recovery.