The pharmacokinetic model, which describes context-sensitive decrement times, has received validation through direct measurement. Further validation has come from the ability of targeted infusion schemes to obtain reliable and stable concentrations of a variety of intravenous drugs. A complete understanding of the concept will enable the appropriate selection of drugs and an appreciation of the strengths and limitations of current drug delivery systems. 相似文献
Study Objective: To determine the duration and recovery profile of maintenance doses of cisatracurium besylate following succinylcholine, and during propofol or isoflurane anesthesia.
Design: Randomized, open-label study.
Setting: Operating suite of a university-affiliated medical center.
Patients: Forty ASA physical status I and II adult patients having elective surgery with general anesthesia lasting longer than 90 minutes.
Interventions: Following a standardized induction sequence, a baseline electromyogram (EMG) was obtained. An intubating dose of intravenous (IV) succinylcholine 1.0 mg/kg was administered. Ventilation was maintained with a face mask until the first twitch (T1) of the evoked train-of-four (TOF) reached 10% of control when tracheal intubation was performed. Spontaneous recovery from neuromuscular blockade was allowed to occur until the first twitch returned to 25% of control. Patients then were randomized to receive cisatracurium as follows. Group 1: 0.025 mg/kg [0.5 × 95% effective dose (ED95)]; Group 2: 0.05 mg/kg (ED95); Group 3: 0.05 mg/kg (ED95); and Group 4: 0.1 mg/kg (2×ED95). Anesthesia for Groups 1 and 2 were maintained with isoflurane 1% to 2%, 66% nitrous oxide (N2O) in oxygen (O2), and in Groups 3 and 4, anesthesia was maintained with propofol 80 to 160 μg/kg/min, 66% N2O in O2. The TOF-evoked EMG was recorded at 10-second intervals. The time for the evoked EMG to spontaneously return to 25%, 50%, and 75% of the original baseline was recorded.
Measurements and Main Results: There were 10 patients in each of the four groups. The duration of action of cisatracurium 0.05 mg/kg (ED95) after an intubating dose of succinylcholine is 24.5 ± 10 minutes and 21.3 ± 9 minutes during anesthesia maintained with isoflurane and propofol, respectively. Doubling the dose of cisatracurium resulted in approximately twice the duration of action (40.2 ± 7 min) during propofol anesthesia. Following a dose of cisatracurium 0.025 mg/kg (0.5×ED95), the T1 of the EMG-evoked response did not decrease below 25% in 7 of 10 patients.
Conclusion: Following succinylcholine, the duration of action of a single dose of cisatracurium 0.05 mg/kg is 20 to 25 minutes during anesthesia maintained with propofol or isoflurane. The duration and recovery profile of cisatracurium is dose dependent during propofol and isoflurane anesthetics. Cisatracurium 0.025 mg/kg is an inadequate maintenance dose following recovery from succinylcholine and it fails to provide adequate surgical relaxation. 相似文献
The decade of the 1990s has seen worldwide emphasis on the containment of healthcare costs. Much of the limitation of cost has been carried out at the perceived potential decrement in the quality and outcome of the delivery of patient care. This concern has not been limited to countries with traditional indemnified insurance (USA) or the more social based healthcare programs of the European countries and Canada. As physicians, we have not effectively utilized research methodology in establishing which therapeutic interventions are both cost effective and beneficial. A concerted worldwide effort by clinicians of all disciplines will be necessary to effect cost reduction and improved outcomes. 相似文献
We assessed differences in food reinforced behavior between obese and lean Zucker rats with a progressive ratio schedule
3 (PR3) in which a subject emitted three additional lever-presses each time a reinforcer was delivered. The number of responses
required for a reinforcer eventually exceeded its value, termed the ”break point”, a sensitive measure of food motivated behavior.
Break points were higher in obese rats than lean controls for grain pellets (27.5 versus 9.5, P=0.01) but not for sweet pellets (51.6 versus 38.5, P=0.31). We determined if naloxone (0.01–3.0 mg/kg, SC), which reduces free food intake in obese Zucker rats, affects food
motivated behavior in obese Zuckers and lean controls. Naloxone reduced break points in both obese and lean rats to a similar
extent when working for either grain pellets or sweet pellets. Under free-access feeding conditions, naloxone again decreased
pellet intake similarly in the obese and lean Zucker rats. Naloxone appeared to decrease free-access pellet consumption to
a greater extent than break point in both groups. These results show that (1) obese rats exhibit higher levels of performance
for food than lean rats only when working for the less valued grain pellet, (2) naloxone reduces both break points and free-access
pellet consumption independent of genotype, and (3) naloxone appears to decrease food more effectively in rats given free
access to food than in rats working for food.
Received: 4 April 1998 / Final version: 19 August 1998 相似文献
Orthogonal field agarose-gel electrophoresis (OFAGE) of chromosomes from translocation-bearing and normalNeurospora crassa strains was utilized, first, to recover cosmids from a translocated region, and second, to map translocation breakpoints. Surprisingly, the right breakpoints in two independently derived, interstitial translocations,T(II III) AR18 andT(II VI)P2869, are within about 5.6 kbp of each other suggesting that this region of linkage group (LG) II may be fragile or otherwise subject to chromosome breakage. Mapping translocation breakpoints through OFAGE, or other similar methods, should allow for DNA sequencing across breakpoints that are not associated with mutant phenotypes or that are not within walking distance of cloned markers. 相似文献
Laparoscopy for colonic diseases began in 1990 and has established a role in benign disease. Early observations and experiences demonstrated feasibility of laparoscopic surgery for a variety of colonic disease processes, but the applicability to colonic carcinoma was unclear. METHODS: In 1990, we began a comparative study of open (OCR)vs.laparoscopic (LCR) approach to colon cancer. The study progressed 65 months, with 224 patients in OCR group and 191 patients in LCR group. Parameters studied are stage, location, length of specimen, number of lymph nodes resected, margins, postoperative course, wound complications, recurrence rates, and immediate and long-term survival. OCR were standardized by one group, and LCR were standardized by a second group. All patients undergoing LCR were given freedom to choose either OCR or LCR, and informed consent was obtained. RESULTS: Equal or greater lymph node retrieval, resections, and distal margins were evident with LCR. Benefits with LCR were shown with shorter hospitalization (5.7vs.9.7 days), less blood loss, less wound problems (1vs.14), and quicker return of bowel function. Survival, recurrence, and death rates were essentially the same. There were no trocar implants in the LCR group. CONCLUSION: After five years, this study shows that laparoscopy does no harm to the patient, offers comparable oncologic resections, and seems to be patient-friendly, with less pain, quicker return of bowel functions, shortened hospitalization, and quicker return to full activity. 相似文献
Summary Transected axons in C57BL/Ola mice survive for extraordinary lengths of time as compared to those of normal rodents. The biological difference in the substrain that confers the phenotype of prolonged axonal survival is unknown. Previous studies suggest the defect to be a property of the nervous system itself, rather than one of haematogenous cells. Neuronal or non-neuronal elements could be responsible for this phenotype. This study was undertaken to determine whether Schwann cells, the most numerous of the non-neuronal cells intrinsic to the peripheral nerve, are responsible for delayed degeneration of transected axons. We created sciatic nerve chimeras by transplanting nerve segments between standard C57BL/6 and C57BL/Ola mice, allowing regeneration of host axons through the grafts containing donor Schwann cells. These nerves were then transected and the time course of axonal degeneration was observed. The results show that fast or slow degeneration is a property conferred by the host, and therefore cannot be ascribed to the Schwann cells. Similarly, transected C57BL/Ola axons in explanted dorsal root ganglia cultures survived longer than transected axons from standard mice. Taken together these results indicate that the responsible abnormality is intrinsic to the C57BL/Ola axon. 相似文献
This retrospective review of seven patients with completely obstructing cancers of the left half of the colon, in addition to other reports in the literature, suggests that subtotal colectomy with primary ileal
1 Clinical data on seven patients who underwent subtotal colectomy for obstructing carcinoma of the left colon: 1975–1982.
proctostomy may be the treatment of choice for those lesions that are technically resectable and located high enough to permit an intraperitoneal ileal proctostomy. The morbidity and mortality is less than that seen with the staged approach and the length of hospitalization is shorter. By eliminating a second or third hospitalization and a temporary colostomy, palliation is better in those patients who ultimately die from recurrent cancer. Furthermore, those patients resected for cure may have increased rates of long-term survival. 相似文献