Patterns of Simian Virus 40 DNA transcription after acute infection of permissive and nonpermissive cells

Small amounts of fractionated, denatured, (32)P-labeled DNA from SV40 virus were incubated with a large excess of the complementary RNA of SV40 prepared in vitro with Escherichia coli RNA polymerase; the viral DNA strands were separated on hydroxyapatite columns. The RNA present in green monkey cells late in the lytic cycle reacted with 40-42% of the strand complementary to the in vitro complementary RNA (minus strand), and 60-64% of the opposite (plus) strand. "Early lytic" RNA failed to significantly interact with the plus strand, but formed stable duplex molecules with 35-39% of the minus strand. The RNA prepared from mouse embryo cells 24 hr after infection with SV40 combined with 35-38% of the minus strand and 60-62% of the plus strand. In all cases, the same regions of either the plus or minus strand appear to be transcribed in permissive and nonpermissive infections.     

Concatemers of alternating plus and minus strands are intermediates in adenovirus-associated virus DNA synthesis.

Replicating DNA molecules of adenovirus-associated virus (AAV) were selectively extracted from KB cells coinfected at 39.5 detrees with a DNA minus, temperature-sensitive mutant of adenovirus 5 (ts125) as helper. Under these conditions AAV DNA replication proceeds normally, but there is little, if any, adenovirus DNA synthesis. An analysis of the replicating molecules in sucrose density gradients reveals that there are AAV DNA intermediates which consist of covalently linked plus and minus DNA strands. Under denaturing conditions, these concatemers are linear single strands whose lengths can reach at least four times the size of the AAV genome. The most abundant concatemeric species is a dimer which presumably exists in vivo as a unit length hairpin. Unit length linear duplexes appear to be immediate precursors of plus and minus progeny strands. These findings are compatible with a self-priming mechanism for the synthesis of AAV DNA.     

Endotoxins enhance hepatocarcinogenesis induced by oral intake of thioacetamide in rats

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Nucleotide sequences of the separate origins of synthesis of bacteriophage G4 viral and complementary DNA strands.

Bacteriophage G4 has physically separated origins of synthesis of its viral and complementary DNA strands. Chain termination and "plus and minus" DNA sequencing methods have been used to obtain the nucleotide sequence of these two origins. The unique origin at which the complementary DNA strand is initiated has located in the untranslated region between genes F and G. This sequence, which has considerable secondary structure, contains a stretch which is complementary to the RNA primer that is observed during synthesis in vitro of the G4 complementary DNA strand [Bouché, J.P., Rowen, L. & Kornberg, A. (1978) J. Biol. Chem., in press]. This G4 origin shows extensive sequence homology with the bacteriophage lambda origin of DNA replication [Denniston-Thompson, K., Moore, D. D., Kruger, D. E., Furth, M. E. & Blattner, F. R. (1977) Science 198, 1051-1056]. The sequence around the site in gene A at which G4 viral DNA strand synthesis is initiated by the nicking action of the cistron A protein is very similar to that of bacteriophage phiX174. An (A + T)-rich stretch flanked by (G + C)-rich sequences may be involved in the interaction between the DNA and protein.     

Initial experience with an implantable cardioverter-defibrillator incorporating cardiac resynchronization therapy

OBJECTIVES: The purpose of this study was to evaluate an implantable cardioverter-defibrillator (ICD) incorporating biventricular pacing. BACKGROUND: Biventricular pacing improves the symptoms of heart failure, a frequent problem in ICD recipients. METHODS: This prospective multicenter study evaluated the safety and efficacy of an ICD with biventricular pacing. RESULTS: A total of 84 patients with a standard ICD indication, symptomatic heart failure, left ventricular (LV) ejection fraction <35% and a QRS duration >130 ms were included in the trial. In 81 of 84 patients the LV lead was successfully implanted. Patients significantly improved in the 6-min hall-walk test (baseline 304 plus minus 131 m, three months 397 plus minus 142 m, p < 0.001), quality of life (baseline 38.9 plus minus 21.2, three months 26.5 plus minus 21.2, p < 0.001) and the New York Heart Association (NYHA) classification (baseline 2.8 plus minus 0.6, three months 2.2 plus minus 0.5). Left ventricular end-diastolic (from 79.6 plus minus 13.0 mm to 73.6 plus minus 12.9 mm, p = 0.002) and end-systolic (from 68.3 plus minus 13.5 mm to 63.9 plus minus 12.9 mm, p < 0.001) diameter decreased, and fractional shortening increased (from 16 plus minus 6% to 18 plus minus 6%, p = 0.018). Of the patients 26 experienced 472 episodes of spontaneous sustained ventricular tachyarrhythmias. All episodes were successfully terminated except for 16 episodes occurring in a patient with incessant ventricular tachycardia. Biventricular antitachycardia pacing was more effective than right ventricular antitachycardia pacing (p < 0.001). During follow-up (median 185 days, range 12 to 344 days) five patients died from progressive heart failure. CONCLUSIONS: Incorporating biventricular pacing in an ICD is feasible and leads to an improvement of heart failure symptoms. Therefore, this therapy may become an option for patients who need ICD therapy in the presence of severe heart failure.     

P-wave dispersion between transcatheter and surgical closure of secundum-type atrial septal defect in childhood

Patients with atrial septal defect have an increased risk for atrial fibrillation. Increased P-wave dispersion predicts the development of atrial fibrillation. The aim of this study was to determine difference in P dispersion between transcatheter closure with Amplatzer septal occluder and surgical closure in childhood. A total of 68 children (the mean age was 7.2 plus or minus 3.3 years; the mean secundum atrial septal defects diameter was 17.3 plus or minus 5.4 millimetres) were evaluated in this study. Transcatheter closure was attempted in 41 children with secundum atrial septal defects, and the defect in 27 patients was closed by surgical techniques. P maximum, P minimum and P dispersion were measured by the 12-lead surface electrocardiography. P maximum, P minimum and P dispersion were found to be similar in patients with pre- and post-procedure (98.0 plus or minus 19.3 versus 95.1 plus or minus 23.0 milliseconds; 68.0 plus or minus 20.8 versus 67.6 plus or minus 24.3 milliseconds, 29.9 plus or minus 11.0 versus 27.1 plus or minus 12.1 milliseconds, respectively). There was no statistical significance in the comparison of P dispersion between the two groups. But in the surgical group, P-wave dispersion was decreased more significantly compared with baseline values (p-value equal to 0.03). In conclusion, there is no P dispersion between transcatheter closure with Amplatzer septal occluder and surgical closure of secundum atrial septal defect.     

Radiosensitivities of DNA molecules in lymphocytes from the circulating blood of man

The radiosensitivities of DNA molecules from lymphocytes of human circulating blood were examined by alkaline sucrose gradient centrifugation. The single-strand breaks of DNA per rad, including the breaks formed under the present alkaline condition, were 1.2 plus or minus 0.1 breaks per 10-12 daltons DNA per rad. When the cells were transformed, the number of breaks was found to increase to 1.8 plus or minus 0.2 breaks per 10-12 daltons DNA per rad. The lymphocytes are capable of rejoining radiation-induced single-strand breaks of DNA. The rate of rejoining was dependent upon types of the suspending medium. The rate increased to ten times of that of the non-transformed cells upon transformation.     

Right heart volume characteristics in transposition of the great arteries.

Right and left heart volume data were obtained during 44 cardiac catheterizations in 24 patients with complete transposition of the great arteries (TGA) prior to "corrective surgery." Patients were divided into three hemodynamic groups: I)TGA with intact ventricular septum, N = 23 studies in 13 patients, ages 1 day-22 months; II)TGA with ventricular septal defect (VSD), N = 12 studies in six patients, ages 7 days-15 months; III)TGA with VSD plus pulmonary stenosis, N = 9 studies in five patients, ages 5 days-5.6 years. In group I, right ventricular end-diastolic volume (RVEDV) averaged 170 plus or minus 52% of normal (P smaller than 0.001), RV ejection fraction (EF) was 0.48 plus or minus 0.09, 74% of normal (P smaller than 0.001), and RV systolic output (SO) was 123 plus or minus 34% (NS). In group II, RVEDV was 163 plus or minus 25% of normal (P smaller than 0.001), RVEF 0.59 plus or minus 0.08, 91% of normal (NS), and RVSO was 158 plus or minus 52% (P smaller than 0.02). In group III, RVEDV averaged 124 plus or minus 26% of normal (P smaller than 0.04), RVEF 0.58 plus or minus 0.15, 89% of normal (NS), and RVSO 125 plus or minus 57% (NS). Right atrial maximal volume was increased in 21 or 22 studies and averaged 185 plus or minus 47% of normal (P smaller than 0.001). RVEDV was greater than left ventricular end-diastolic volume in all but one patient in group I, but RVEDV/LVEDV was smaller than 1.00 in four VSD patients with very large pulmonary flows. A majority of patients with TGA without VSD have abnormal right heart function as indicated by an increased RVEDV and a low ejection fraction. Longitudinal studies of right ventricular performance in these patients continue to be important in assessment of current methods of therapy.     

肝癌组织中丙型和乙型肝炎病毒基因状况研究

采用逆转录巢式ＰＣＲ技术检测了５１例ＨＣＣ患者的肝癌及癌周肝组织中ＨＣＶＲＮＡ正负链，同时以巢式ＰＣＲ技术检测了这些组织中的ＨＢＶＤＮＡ。结果，１１．８％（６／５１）检出组织中ＨＣＶＲＮＡ正链：其中５例在癌周肝组织，２例在癌组织中检测出ＨＣＶＲＮＡ负链，由于负链ＲＮＡ为ＨＣＶ的复制中间体，不释放到细胞外，其检出ＨＣＶ感染与ＨＣＣ关系的研究提供了进一步的病因证据，组织中ＨＢＶＤＮＡ检出率高达９２．２     

Endoscopic implantation of a biopolymer in the lower esophageal sphincter for gastroesophageal reflux: a pilot study

BACKGROUND: GERD is the most frequent disorder of the esophagus. Endoscopic minimally invasive treatment is desirable. However, the results of injection techniques have been disappointing. METHODS: A pilot study was conducted in patients with GERD, who required continuous therapy with a proton pump inhibitor, in which ethylene-vinyl-alcohol was injected into the muscle of the gastric cardia. Primary endpoints were the safety of the procedure, the effect on lower esophageal sphincter pressure and the stability of the injected material. A secondary endpoint was the effect on heartburn score after discontinuation of treatment with a proton pump inhibitor. RESULTS: Ethylene-vinyl-alcohol injection into the cardia resulted in circular diffusion of the product in 10 of 15 cases, suggesting that implantation into the muscle is feasible. Lower esophageal sphincter pressure was increased in 13 of 15 cases at 1 month and was sustained at a median follow-up of 6 months (range 4-12 months). Mean plus minus SEM of lower esophageal sphincter pressures (15 patients) were 12.2 plus minus 0.9, 18.7 plus minus 1.5 (p = 0.001 at baseline), and 16.7 plus minus 1.3 mm Hg (p = 0.038 from baseline) at, respectively, baseline, 1 month follow-up, and final follow-up. There was also a sustained reduction in heartburn score (off proton pump inhibitor) (3.40 plus minus 0.13 vs. 1.53 plus minus 0.24 and 1.87 plus minus 0.26 at baseline vs. 1 month and final follow-up, respectively; p < 0.01). Nine of the 15 patients had more than 50% of the injected material in place at second follow-up (at 6 months for 8 patients; at 12 months for 1 patient). In only 2 patients was there loss of more than 75% of injected ethylene-vinyl-alcohol. Persistence of greater than 50% of the material was associated with achievement of a circular injection. Only 4 patients had to resume therapy with a proton pump inhibitor. Mild retrosternal discomfort was observed in 8 patients; this disappeared in all cases after a maximum of 3 days. CONCLUSIONS: Ethylene-vinyl-alcohol implantation in the muscle of the cardia is feasible and safe. It leads to a sustained increase in resting lower esophageal sphincter pressure. This is associated with a sustained improvement in heartburn score for patients who previously required continuous therapy with a proton pump inhibitor.