Tissue actions of bipolar scissors compared with monopolar devices

OBJECTIVES: To establish whether bipolar scissors offer equivalent cutting performance compared with monopolar scissors and to compare extent of thermal coagulation injury using two electrosurgical generators. DESIGN: Eighteen female rabbits' uterine horns were cut using controlled velocity at several different wattages with either bipolar or monopolar scissors. The specimens were examined microscopically and zones of thermal necrosis were measured using a stage micrometer against a 1 mm standard. RESULTS: Bipolar scissors cut equally well compared with monopolar scissors and showed significantly less thermal injury. When coupled to a constant voltage generator both the bipolar and monopolar scissors performed better. CONCLUSION: Bipolar scissors offer the surgeon significant safety advantages and equivalent or better performance compared with monopolar scissors when used for laparoscopic surgery.     

Six-month outcome of critically ill patients given glutamine-supplemented parenteral nutrition

Tetrahydrobiopterin is an essential cofactor required for activity of nitric oxide synthases. Existing evidence suggests that, during activation of constitutive and inducible isoforms of nitric oxide synthase, tetrahydrobiopterin is needed for allosteric and redox activation of enzymatic activity. However, precise mechanisms underlying the role of tetrahydrobiopterin in regulation of nitric oxide formation is not fully understood. In cerebral and peripheral arteries, increased availability of tetrahydrobiopterin can augment production of nitric oxide. In contrast, in arteries depleted of tetrahydrobiopterin, production of nitric oxide is impaired. Proinflammatory cytokines enhance mRNA expression of the rate-limiting enzyme of tetrahydrobiopterin biosynthesis, GTP cyclohydrolase I and stimulate production of tetrahydrobiopterin. The ability of vascular tissues to synthesize tetrahydrobiopterin plays an important role in regulation of nitric oxide synthase under physiological conditions as well as during inflammation and sepsis. More recent studies concerning expression and function of recombinant nitric oxide synthases suggest that availability of tetrahydrobiopterin is important for production of nitric oxide in genetically engineered blood vessels. In this review, mechanisms regulating availability of intracellular tetrahydrobiopterin and its role in control of vascular tone under physiological and pathological conditions will be discussed.     

Suspected skeletal dysplasias: femur length to abdominal circumference ratio can be used in ultrasonographic prediction of fetal outcome

OBJECTIVES: Skeletal dysplasias are a group of bone growth disorders, some of which can be recognized prenatally. Certain types of skeletal dysplasias result in a lethal fetal outcome. The ability to predict this outcome prenatally would be important in counseling parents. This study evaluated the ratio of femur length to abdominal circumference as a predictor of fetal outcome in cases of suspected skeletal dysplasia. STUDY DESIGN: This 3-year retrospective study identified 18 cases of prenatally suspected skeletal dysplasia from a population of approximately 35,000 fetuses undergoing prenatal ultrasonography. The femur length/abdominal circumference ratio was calculated and compared with fetal-neonatal outcomes and diagnoses. RESULTS: Eighteen cases of suspected skeletal dysplasia were identified, and the femur length/abdominal circumference ratio was found to be a good predictor of fetal outcome independent of gestational age. A ratio < 0.16 resulted in a lethal outcome in nine of nine cases. Conversely, a ratio > or = 0.16 resulted in a diagnosis of a nonlethal form of skeletal dysplasia or a diagnosis that ruled out any form of skeletal dysplasia in nine of nine cases. CONCLUSIONS: The femur length/abdominal circumference ratio may be useful to predict a lethal fetal outcome when ultrasonography indicates a possible skeletal dysplasia.