Population Development of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in Landrace Bean Varieties Occurring in Southwestern Amazonia.

The common bean, Phaseolus vulgaris (L.), is one of the most important sources of protein worldwide, and Latin America is one of the recognized centers of diversity of this species. However, storage of this product after harvest is not feasible because of bruchid attacks. This study determined the accumulated normalized rate of emergence and the daily emergence rate of Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae:Bruchinae) in five landrace varieties of common bean (BRL 01, SNA 01, RDR 01, RBC 01, and RBC 13) that occurin southwestern Amazonia. These varieties were selected for this study because they are well-distributed throughout the Amazonian communities. Beans of each variety were infested with 50 unsexed adults, and the insects were removed 13 d after beginning the bioassays. The adult progeny obtained from the feeding substrate were counted and removed every other day after the first emergence, until the end of the emergence period. Differences were observed in the calculated rates of development; however, the time required for development and emergence of the insects was independent. Of the five varieties of bean investigated, we observed that the RDR 01, BRL 01, and SNA 01 cultivars are resistant to Z. subfasciatus; the results indicate that the use of these three varieties can reduce problems associated with bruchid attacks and enable storage of the product after harvesting.

DNA elimination in embryogenic development of Pennisetum glaucum x Pennisetum purpureum (Poaceae) hybrids.

Interspecific hybridization between Napier grass (Pennisetum purpureum), which is widely grown in Brazil for cattle forage, and pearl millet (Pennisetum glaucum) has been used as a breeding strategy for the development of improved cultivars. However, the hybrid between these two species is sterile due to its triploid condition (2n = 3x = 21 chromosomes), which hinders its use in crop breeding programs. It is known that genomic alterations result from the hybridization process. In order to measure the loss of DNA during embryo development, we used flow cytometry to estimate the nuclear DNA content of triploid and tetraploid embryos produced by interspecific hybridization between Napier grass and pearl millet. The triploid and tetraploid hybrids had a mean DNA content of 4.99-4.87 and 5.25-4.84 pg, at 10 and 30 days after pollination, respectively. The mean reduction in DNA content was higher in the tetraploid hybrids. The flow cytometry results revealed progressive genomic instability in these triploid and tetraploid hybrids, with this instability causing significant alterations in the DNA content of the hybrids.

Effects of propranolol on the QT dispersion in congestive heart failure.

OBJECTIVE: Studies have shown that therapy with beta-blockers reduces mortality in patients with heart failure. However, there are no studies describing the effects of propranolol on the QT dispersion in this population. The objective of this study was to assess the electrophysiological profile, mainly QT dispersion, of patients with heart failure regularly using propranolol. METHODS: Fifteen patients with heart failure and using propranolol were assessed over a period of 12 months. Twelve-lead electrocardiograms (ECG) were recorded prior to the onset of beta-blocker therapy and after 3 months of drug use. RESULTS: A significant reduction in heart rate, in QT dispersion and in QTc dispersion was observed, as was also an increase in the PR interval and in the QT interval, after the use of propranolol in an average dosage of 100 mg/day. CONCLUSION: Reduction in QT dispersion in patients with heart failure using propranolol may explain the reduction in the risk of sudden cardiac death with beta-blocker therapy, in this specific group of patients.

Role of surgery in head and neck cancer with fixed nodes.

In a series of 51 cases of Stage IV head and neck carcinomas, 12 selected patients were studied retrospectively, in order to determine the role of surgery in their management. Two patients who received a tumoricidal dose of radiation prior to radical neck dissection survived over five years, but no viable tumor was found in either specimen, suggesting a radiation cure. Nine patients died within three years, with either local recurrence or distant metastases; one patient died of asphyxiation, without disease, within five months. It appeared that surgery played no substantial role in improving the survival of the patients with head and neck cancer with fixed nodes.