Real-time cerebral angiography: sensitivity of a new contrast-specific ultrasound technique.

BACKGROUND AND PURPOSE: To test a new contrast-specific sonography imaging method that offers visualization of the intracranial vasculature in a manner similar to that seen on angiography. MATERIALS AND METHODS: Thirty patients (35 sonography studies total) were included in the study after they provided written informed consent. The patients were scanned through the temporal bone window from both sides after intravenous injection of an ultrasound contrast agent (UCA; perflexane lipid microspheres [Imagent]). The goal was to visualize the intracranial arteries, including the middle (M1-M3), anterior (A1 and A2), and posterior (P1-P3) cerebral arteries, using an axial scanning plane. The studies were performed using a contrast-specific imaging mode, based on a phase inversion technique (transcranial ultrasound angiography [tUSA]). For sensitivity, the results were compared with x-ray angiography as the "gold standard." For interobserver reliability, 24 of 35 sonography studies were evaluated by 2 physicians with little training in transcranial sonography and by a seasoned sonographer. RESULTS: The sensitivity of tUSA ranged between 0.778 (95% confidence interval [CI] of 0.577-0.914) and 0.963 (95% CI of 0.810-0.999). The sensitivities were similar among physicians with little training in transcranial sonography and the seasoned sonographer, indicating high inter-rater reliability. Overall, tUSA provided high anatomic resolution and vascular delineation even of small vessels in the millimeter range. At peak intensity, no UCA-related artifacts were observed. CONCLUSION: tUSA provides images of the intracranial arteries similar to those obtained at angiography with high anatomic resolution, reasonable sensitivity, and interobserver reliability.

Reduced oxygen tension and EDTA improve bovine zygote development in a chemically defined medium.

Bovine zygotes produced by in vitro oocyte maturation and fertilization were cultured for 7.5 d in a chemically defined medium without serum or proteins, except .12 IU/mL of insulin. In Exp. 1, embryos were cultured in approximately 20% oxygen (i.e., 5% CO2 in air) or 5% CO2; 5% O2; 90% N2, with the metal chelators EDTA or diethylenetetraaminopentaacetic acid (DTPA) at 0, 5, 25, or 125 microM. More (P < .01) embryos developed to blastocysts at 5% O2 (17%) than at -20% O2 (7%). Also, embryos grown at 5% O2 averaged more cells than embryos cultured at -20% O2 (38 vs 29 cells for morulae and blastocysts and 15 vs 12 cells including all embryos; P < .05). There were interactions (P < .01) among chelator, concentration of chelator, and oxygen tension. The most efficacious treatments were 5 microM EDTA at 5 or -20% O2 (24 and 20% blastocysts), 5 microM DTPA at 5% O2 (28% blastocysts), and 25 microM EDTA at 5% O2 (25% blastocysts). High concentrations of either chelator were detrimental, especially at -20% O2. In Exp. 2, a smaller range of chelator concentrations was compared (EDTA: 3, 9, 27, or 81 microM, DTPA: 3 or 15 microM) in 5% O2. More embryos developed to blastocysts and expanded blastocysts with 3 microM EDTA than the control without a chelator (20 and 16% vs 7 and 3%, respectively; P < .05). However, in Exp. 3, which concerned embryo development in .33, 1, 3, or 27 microM EDTA and .33, 1, or 3 microM DTPA, no concentration of either chelator was better (P > . 1) than the control.

Culture of in vitro-produced bovine embryos with vitamin E improves development in vitro and after transfer to recipients.

Detrimental effects of oxygen-derived free radicals on embryos during culture have been demonstrated in several species. Vitamin E occurs naturally in cell membranes and protects cells from oxidative stress. Under some conditions, vitamin C acts synergistically to enhance the antioxidant effects of vitamin E, a benefit that may be further enhanced by EDTA. The present experiments concerned culture of bovine embryos derived from in vitro-matured, fertilized oocytes with vitamin E, vitamin C, and EDTA in a chemically defined culture medium + 0.2% BSA at 5% O(2), 5% CO(2), and 90% N(2). In the first experiment, more zygotes developed to expanded blastocysts (17%, n = 224, P < 0.05) when culture medium contained 100 microM vitamin E than in control medium (11%, n = 234). Development to early, expanded, and hatched blastocysts was lower with vitamins E and C combined than with vitamin E alone (15%, 9%, and 2% vs. 24%, 17%, and 5%, respectively; P < 0.05), as was the mean number of cells per blastocyst (56 vs. 84, P < 0.05). Addition of EDTA (3 microM) failed to improve development over that in culture with vitamin E + vitamin C. In experiment 2, in vitro-produced embryos cultured 5.5 days in medium with or without 100 microM vitamin E were transferred nonsurgically to recipient cows and heifers and then collected nonsurgically 7 days later. Embryos cultured with vitamin E (n = 37) were approximately 63% larger in surface area than controls (1.16 mm(2) vs. 0.71 mm(2) surface area; n = 27, P < 0.04).

Evaluation of pulmonary infections in patients with extremity fractures and blunt chest trauma.

The use of preventive antibiotics has become the standard of care in the management of patients with multiple trauma who have injuries at risk for infection. In many areas of surgical practice, preventive antibiotic utilization has been restricted to the perioperative period only. In this study we reviewed a series of trauma patients with combined blunt chest injuries and extremity fractures to determine whether the duration of postoperative antibiotic administration would have adverse effects upon nosocomial pneumonia rates and severity.

Falls and ejections from pickup trucks.

The medical records of 50 patients who sustained injuries during falls or ejections from pickup truck beds and were admitted to the University of New Mexico Level I Trauma Center between January 1985 and December 1989 were retrospectively examined. Falls and ejections commonly involve young adults, and usually occur in the summer months during the afternoon or evening. Twenty-three individuals were thrown from the pickup truck bed during a motor vehicle collision and 27 simply fell out, and this distinction was not related to age or ethanol use. Although those thrown from the pickup truck bed during a crash were less severely injured (average ISS 15.4) than those who simply fell from the bed (average ISS 17.4), this difference was not statistically significant. Mortality was equal in these two groups, with three deaths occurring in each group. Overall, injuries incurred during falls and ejections were more serious than those incurred in MVCs (average ISS 16.5 vs. 14.5, p = 0.06). The head was the most frequently injured body region following falls or ejections (68%), followed by the extremities (46%), the face (28%), the thorax (22%), and the abdomen (10%). Every death in this series was attributed to a head injury. The overall mortality for the series was 12%. Sixteen additional fatalities from falls and ejections during the study period were discovered in a review of the records of the State Medical Examiner. The average age of this cohort was 24 years. Fifteen of these deaths were the result of falls rather than ejections (94%), and 13 were attributed to head injuries (81%).(ABSTRACT TRUNCATED AT 250 WORDS)

Protein and energy tolerance by stressed geriatric patients.

Nutritional support of stressed geriatric patients remains empiric and has classically been limited by tolerance. Although the hypermetabolic response is known to increase protein and calorie demands, tolerance to increased loads of delivered nutrients in older patients has been questioned. We compared tolerance to nutrient delivery and nitrogen metabolism in 38 stressed surgical patients over age 65 to 38 Injury Severity Score or disease matched younger controls. Twenty-seven of the 31 geriatric patients (87%) who maintained normal renal function (serum creatinine less than 2.0 mg/dl) became azotemic (BUN greater than 30) while receiving 1.5 to 2.0 g of protein per kilogram of ideal body weight compared to only 21% of controls. This phenomenon led to inaccuracies in 17% of geriatric nitrogen balance studies because of unaccounted for serum accumulation of urea nitrogen (compared to only 6% in the control group). When calculated protein requirements were administered to the geriatric group, the mean nitrogen balance was -1.6. Resting energy expenditure as measured by indirect calorimetry demonstrated a strong correlation between actual calorie expenditures and calculated needs based on the Harris-Benedict basal energy expenditure (BEE) multiplied by an activity factor of 1.2 and a stress factor of 1.75 for trauma (r = 0.86, P less than 0.05) or 1.5 for general surgery patients (r = 0.72, P less than 0.05). In summary, energy requirements by stressed geriatric patients can be closely defined by calculation of the Harris-Benedict BEE in conjunction with appropriate activity and stress factors. However, attempts to deliver traditional levels of protein lead to azotemia and are frequently unsuccessful in achieving positive nitrogen balance.(ABSTRACT TRUNCATED AT 250 WORDS)