Dicistronic expression of the green fluorescent protein and antibiotic resistance genes in the plastid for selection and tracking of plastid-transformed cells in tobacco.

A plastid transformation vector was constructed for dicistronic expression of the aminoglycoside 3'-adenyltransferase (aadA) and green fluorescent protein (gfp) genes under the control of the plastid rrn promoter. Gold particles coated with the vector DNA were bombarded onto tobacco leaf explants using a particle delivery system. Leaf explants produced adventitious shoots when cultured on shoot-inducing medium containing 500 mg l(-1) spectinomycin. Shoots that exhibited green fluorescence under UV light were selected. Southern blot analysis detected the presence of the aadA and gfp genes between trnA and trnI in the plastid genome. Northern blot analysis revealed that the aadA and gfp genes were both properly transcribed into a dicistronic transcriptional unit. The expression of the gfp gene in the plastid enabled separation of transformed chloroplasts from wild-type chloroplasts in the protoplast under a fluorescent microscope. The overall results indicate that dicistronic expression of the aadA and gfp genes in the plastid simplifies gene manipulation, facilitating selection and tracking of plastid-transformed cells.

Prehospital bicarbonate use in cardiac arrest: a 3-year experience.

The American Heart Association no longer recommends the routine use of sodium bicarbonate in cardiac arrests. Reasons cited include the lack of documented effect on clinical outcome and potential adverse effects of metabolic alkalosis and hypernatremia. We reviewed 36 months of experience with 619 nontrauma adult, prehospital cardiac arrest patients to identify 273 successful resuscitations who had emergency department blood gases and electrolytes performed. Determination of complications associated with prehospital intravenous sodium bicarbonate and its impact on survival in resuscitated patients was undertaken. Fifty-eight patients did not receive sodium bicarbonate (NO HCO3 group) and had short cardiopulmonary resuscitation (CPR) times (7.4 +/- 5.5 minutes). Two hundred fifteen patients did receive sodium bicarbonate (HCO3 group) and had significantly longer CPR times (23.3 +/- 13.5 minutes, P less than or equal to .001). Both groups demonstrated routine early chest compression and hyperventilation as evidenced by no significant difference in paramedic response time or rate of intubations. Initial emergency department blood gas results of both groups were not significantly different. No patients in the NO HCO3 group had hypernatremia (sodium [Na]+ greater than 150), whereas four patients (2%) in the HCO3 group were hypernatremic. Eight patients (14%) in the NO HCO3 group and 37 patients (17%) in the HCO3 group were alkalotic with pH values greater than 7.49 (P = NS). Six patients (10%) of the NO HCO3 group and 24 patients (11%) of the HCO3 group had a metabolic component to the alkalosis as defined by a positive base excess value (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)