Marking Drosophila suzukii (Diptera: Drosophilidae) With Rubidium or 15N.

Drosophila suzukii Matsumura (Diptera: Drosophilidae) has caused significant economic damage to berry and stone fruit production regions. Markers that are systemic in plants and easily transferred to target organisms are needed to track D. suzukii exploitation of host resources and trophic interactions. High and low concentrations of the trace element, rubidium (Rb), and the stable isotope, 15N, were tested to mark D. suzukii larvae feeding on fruits of enriched strawberry plants grown in containers under greenhouse conditions. Fly marker content and proportion of flies marked 1, 7, and 14 d after emergence from enriched fruits and fly dry mass were analyzed. Nearly 100% of the flies analyzed 14 d after emerging from 15N-enriched plants were marked, whereas only 30-75% and 0-3% were marked 14 d after emerging from high and low Rb concentration plants, respectively. Rapid Rb decay, strong 15N persistence, and the economics of using these markers in the field to elucidate D. suzukii pest ecology are discussed.

Morphology of the human thyroglossal tract: a histologic and macroscopic study in infants and children.

The anatomic development of thyroglossal tract remnants is not understood at present. For analysis of morphology and growth patterns of thyroglossal tract remnants, we used histologic whole organ serial sections to determine developmental changes through the first years of life. Larynges of 58 infants and children ages 1 month to 13 years were obtained in whole organ serial step-sections in an axial plane. The slides were stained with hematoxylin and eosin, Alcian blue, and periodic acid-Schiff stains. Altogether, 3,247 histologic slices were examined. The resulting data were then correlated with the age and sex of the specimens. We found, in 24 cases (41.3%), remnants of the thyroglossal tract or ectopic thyroid tissue. In 4 specimens (16.6%), a complete thyroglossal tract could be observed that presented a ventral path in relation to the hyoid bone with no contact with the perichondrium of the cartilage. Hormonal activity of ectopic thyroid tissue was proven in 20 cases (34.5%). Thyroid follicles were located in 2 cases (3.5%) in the hyoid bone. The thyroglossal ducts revealed a modest tendency for a left-sided pathway, whereas thyroid follicles were located more on the right paramedian side. Morphometric data on the development and structure of the thyroglossal tract and the thyroid follicles during infancy and childhood are presented. The study provides quantitative data of clinical interest that elucidate the anatomy of thyroglossal tract remnants. In addition, our investigation supports Sistrunk's operative approach for avoiding recurrences in the treatment of thyroglossal duct cysts.

Cardiac performance testing by volume loading and lower-extremity compression.

Cardiac performance was tested with a combination of volume loading and lower-extremity compression by an anti-g suit in 11 patients scheduled for aortic operations. The mean response of cardiac output (CO) to volume loading and anti-g suit compression was flat, despite a significant rise in pulmonary capillary wedge pressure (PCWP). Right to left intrapulmonary shunt was unchanged by the testing procedure. The low mean wedge pressure reemphasizes the need for preoperative insertion of a Swan-Ganz catheter and for measurement of PCWP and Co to provide optimal fluid treatment to each patient who undergoes an aortic reconstructive operation.

Positive end-expiratory pressure in weaning patients from controlled ventilation. A prospective randomised trial.

Twenty-five patients in acute respiratory failure were randomised to receive either 5 cm of positive end-expiratory pressure (P.E.E.P.) or no-P.E.E.P. while weaning from controlled ventilation. The use of P.E.E.P. resulted in a significant reduction in the increase in alveolar-arterial oxygen tension gradient (AaDO21) which occurred in the group of patients who were converted from controlled ventilation to spontaneous ventilation without P.E.E.P. Patients who weaned without P.E.E.P. had a mean increase in AaDO21 of 102+/-35 mm Hg S.E. while those who weaned with P.E.E.P. had a mean increase of only 10+/-22 mm Hg (P less than 0-03). The use of P.E.E.P. was also associated with a significant improvement in the vital capacity and the maximum inspiratory force. Patients who weaned with P.E.E.P. had an increase in vital capacity of 258+/-108 ml (P less than 0-05) and an increase in inspiratory force of -15+/-5 cm H2O (P less than 0-01), while patients who weaned without P.E.E.P. did not have significant changes in these measurements. The use of P.E.E.P. during weaning may be helpful in patients who fail to wean because of the development of hypoxaemia due to rapid alveolar collapse, since P.E.E.P. appears to minimise the increase in intrapulmonary right-to-left shunt which normally occurs during weaning from controlled ventilation.

Prevention of gram-negative bacillary pneumonia using polymyxin aerosol as prophylaxis. II. Effect on the incidence of pneumonia in seriously ill patients.

All 744 patients admitted to a Respiratory-Surgical Intensive Care Unit (RSICU) were included in a prospective study of the effects of a polymyxin (2.5 mg/kg body wt/day in six divided doses) or a placebo aerosol sprayed into the posterior pharynx and tracheal tube (if present), during 11 alternating 2-mo treatment cycles. The incidence of upper airway colonization in the RSICU with Pseudomonas aeruginosa was 1.6% during the polymyxin treatment cycles (total 374 patients) and 9.7% during the placebo cycles (370 patients) (X2 equals 23.2, P less than 0.01). 3 patients in the RSICU acquired Pseudomonas pneumonia, as defined by independent "blinded" assessors, during the polymyxin cycles while 17 acquired a Pseudomonas pneumonia during the placebo cycles (X2 equals 10.2, P less than 0.01). The overall mortality was similar in both placebo and polymyxin-treated groups (12.2 vs. 12.0%). Systemic antibiotic usage was similar in the different cycles; 49% of patients in the placebo and 53% in the polymyxin-treated groups received systemic antibiotics while in the RSICU.