Homogenous distribution of fast response action potentials in canine pulmonary vein sleeves: a contradictory report

Pulmonary veins may serve as source of ectopic focus (or foci) in initiating atrial tachyarrhythmias in human beings. However, the animal model for such focal atrial fibrillation is still lacking and cellular mechanism for arrhythmias remains to be studied. Recently, a series of reports of cellular electrophysiological characterization of pulmonary vein sleeves demonstrated an extremely high incidence of automaticity (varied from 40 to 76%) and triggered activity (from 0 to 44%) in normal healthy control dogs and rabbits. The present study was therefore designed to re-investigate the cellular electrophysiological properties of canine pulmonary veins. Intracellular action potentials were characterized in pulmonary vein sleeves in 50 normal healthy dogs. Conventional glass microelectrode recording technique was used. Experiments were focused on the incidence of automaticity and triggered activity in pulmonary vein sleeve tissues. Surprisingly, our results showed that all pulmonary vein sleeves tissues in these dogs displayed fast-response action potentials under the well-controlled experimental condition (100%, n=50). No spontaneous pacemaking activities, early or delayed afterdepolarisations were observed (0%, n=50). No high-frequency spikes or irregular rhythm could be recorded in all experiments (0%, n=50). Both the frequency response and membrane responsiveness of the pulmonary vein action potentials were characterized. No electrophysiological inhomogeneity between the distal and the proximal part of the sleeves was observed. In conclusion, canine pulmonary vein sleeves do not display arrhythmogenic activities under normal physiological conditions. The possible explanations for the controversy in pulmonary veins electrophysiology were discussed.     

Myoclonic seizure in the postanesthesia care unit after thoracic laminectomy

IMPLICATIONS: We report a patient who developed myoclonic seizure in the postanesthesia care unit after thoracic laminectomy. Expeditious diagnostic evaluation of unrecognized dura tear during surgery must be instituted immediately to avoid untoward sequelae. Specific treatment in addition to supportive care is required if the diagnosis is to be clearly identified.     

DNA methylation analysis: a powerful new tool for lung cancer diagnosis

Carcinoma of the lung is the most common cause of cancer death worldwide. The estimated 5-year survival ranges from 6-16%, depending on the cell type. The best opportunity for improving survival of lung cancer patients is through early detection, when curative surgical resection is possible. Although the subjects at increased risk for developing carcinoma of the lung (long-term smokers) can be identified, only 10-20% of this group will ultimately develop the disease. Screening tests of long-term smokers employed to date (radiography and sputum cytology) have not been successful in reducing lung cancer mortality. The application of molecular markers specific for lung cancer offers new possibilities for early detection. Hypermethylation of CpG islands in the promoter regions of genes is a common phenomenon in lung cancer, as demonstrated by the analysis of the methylation status of over 40 genes from lung cancer tumors, cell lines, patient sputum and/or serum. Determination of the methylation patterns of multiple genes to obtain complex DNA methylation signatures promises to provide a highly sensitive and specific tool for lung cancer diagnosis. When combined with the development of non-invasive methods to detect such signatures, this may provide a viable method to screen subjects at risk for lung cancer.     

Improvement of local control of T3 and T4 nasopharyngeal carcinoma by hyperfractionated radiotherapy and concomitant chemotherapy

PURPOSE: When the primary tumor of nasopharyngeal carcinoma (NPC) is treated at the base of skull and intracranium with conventional radiotherapy, the result is generally poor. In this report, we investigated whether hyperfractionated radiotherapy (HFRT) and concomitant chemotherapy (CCT) could achieve better local control and survival in NPC patients with T3 and T4 lesions. PATIENTS AND METHODS: Forty-eight patients (11 T3 and 37 T4 NPC) were treated with HFRT and CCT. HFRT was administered at 1.2 Gy per fraction, two fractions per day, Monday-Friday for 62 fractions for a total dose of 74.4 Gy. Concomitant chemotherapy consisting of cis-diamino-dichloroplatinum (CDDP) alone or CDDP and 5-fluorouracil was delivered simultaneously with radiotherapy during Weeks 1 and 6. Adjuvant chemotherapy consisted of CDDP and 5-fluorouracil for 2 to 3 cycles and was given monthly beginning 1 month after completion of radiation. RESULTS: With a median follow-up of 57 months (range: 28-94 months), the 3-year locoregional control rate was 93%, the disease-free survival rate was 71%, and the overall survival rate was 72%. For T4 patients, the 3-year locoregional control rate was 91%, disease-free survival was 62%, and overall survival was 63%. The major acute toxicity was Grade 3 mucositis in 73% and Grade 2 weight loss in 31% of patients. Fifty percent of patients were tube fed. Most patients tolerated the combined modality treatments relatively well; 88% of patients completed their radiation treatment within 8 weeks. CONCLUSION: HFRT and CCT for T3 and T4 NPC were associated with excellent local control and improved survival. The treatment-related toxicity was acceptable and reversible. We would recommend using HFRT with CCT for advanced T-stage NPC if the three-dimensional conformal radiation planning shows a significant portion of the brainstem to be inside the treatment field.     

Neonatal outcome of infants born after in vitro fertilization at National Taiwan University Hospital.

BACKGROUND AND PURPOSE: This study compared the neonatal outcome between infants born after in vitro fertilization (IVF) and after natural conception at National Taiwan University Hospital. METHODS: All medical records of women who underwent IVF and gave birth at our hospital from January 1995 to December 1996 were reviewed. The charts of their offspring were also reviewed. We compared the neonatal outcome of infants born after IVF with that of infants born after natural conception. Neonatal outcome was evaluated based on preterm birth, very low birth weight (VLBW), perinatal morbidity, and neonatal mortality. RESULTS: A total of 75 women underwent IVF and gave birth to a total of 100 live newborns and two fetuses with intrauterine death during the 2-year study period. Among these newborns, the prevalence of preterm birth was 28%, of perinatal morbidity was 17%, and of neonatal mortality was 3%, which were significantly higher than those among the 7,736 neonates born after natural conception. However, the rate of VLBW was similar between the two groups. The rate of preterm birth for twin pregnancies were higher than that for singleton pregnancies in both groups. CONCLUSION: This study showed that infants born after IVF had a higher risk of preterm birth and higher perinatal morbidity and neonatal mortality.     

Adjuvant sequential chemotherapy with doxorubicin plus cyclophosphamide, methotrexate, and fluorouracil (ACMF) with concurrent radiotherapy in resectable advanced breast cancer

Doxorubicin (Adriamycin) is an anthracycline effective in breast cancer. Despite a worldwide acceptance of Adriamycin in the adjuvant chemotherapy to maximize the survival benefit in the higher risk patients with breast cancer with promising results, oncologists in general do not favorably consider anthracyclines in the adjuvant treatment setting because of concern about the acute and chronic drug-related toxicity. For high-risk patients with breast cancer with more than three positive axillary lymph nodes, this series adopted a modified sequential regimen of ACMF first with Adriamycin (A) as a single agent in 3-weekly administration for three courses, and then a combination of cyclophosphamide, methotrexate, fluorouracil (CMF) every 3 to 4 weeks for six courses given in an outpatient setting concurrent with radiation therapy as an adjuvant treatment. A total of 56 patients underwent modified radical mastectomy and 3 others breast conservation surgery for their invasive breast cancer. Forty-seven (84%) patients completed the intended adjuvant treatment and 1 patient died of infection from treatment-related neutropenia. As a whole, the 3-year overall survival and disease-free survival rates of 56 patients analyzed were 82.3% and 64.4%, respectively. In this high-risk group, patients with four to nine positive nodes showed a slightly better trend of survival than those with 10 or more positive nodes without reaching statistically significant difference (36-month overall survival: 90.9% vs. 72.5%, p = 0.06; disease-free survival: 78.7% vs. 47.8%, p = 0.38). In this entire group of patients, locoregional recurrence was absent. A total of 55 episodes of grade III and IV hematologic toxicity were observed, with only one death from neutropenic sepsis. This modified ACMF regimen offers a good survival rate in breast cancer patients with more than three positive axillary lymph nodes. When these patients are carefully managed, the morbidity and mortality related to the treatment are low.     

Diseases of comfort: primary cause of death in the 22nd century

CONTEXT: The world has started to feel the impact of a global chronic disease epidemic, which is putting pressure on our health care systems. If uncurbed, a new generation of "diseases of comfort" (such as those chronic diseases caused by obesity and physical inactivity) will become a major public health problem in this and the next century. OBJECTIVE: To describe the concept, causes, and prevention and control strategies of diseases of comfort. METHODS: Brokered by a senior research scientist specialised in knowledge translation, a chair, a president, and a past president of national public health associations contributed their views on the subject. RESULTS: Diseases of comfort have emerged as a price of living in a modern society. It is inevitable that these diseases will become more common and more disabling if human "progress" and civilisation continue toward better (more comfortable) living, without necessarily considering their effects on health. Modern technology must be combined with education, legislation, intersectoral action, and community involvement to create built and social environments that encourage, and make easy, walking, physical activity, and nutritious food choices, to reduce the health damaging effects of modern society for all citizens and not only the few. CONCLUSIONS: Public health needs to be more passionate about the health issues caused by human progress and adopt a health promotion stance, challenging the assumptions behind the notion of social "progress" that is giving rise to the burden of chronic disease and developing the skills to create more health promoting societies in which individual health thrives.     

Use of the biotin-avidin system to study the specificity of antibodies against respiratory syncytial virus.

To characterize the specificity of monoclonal antibodies against respiratory syncytial virus, we developed a technique which combined the biotin-avidin system, immunoprecipitation, and transblot electrophoresis. The viral proteins were first biotinylated and then immunoprecipitated with a monoclonal antibody or respiratory syncytial virus immune serum, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and electrophoretically transferred to nitrocellulose paper. The protein bands were located on the paper with avidin-peroxidase plus a precipitable substrate. This procedure gave reproducible results qualitatively similar to those obtained by radioimmunoprecipitation but without the cost, risk of radiation exposure, or disposal problems of radioisotopes. This procedure should have widespread applications.