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61.
62.
Serum and Cerebrospinal Fluid Pharmacokinetics of Intravenous and Oral Lamivudine in Human Immunodeficiency Virus-Infected Children 总被引:3,自引:3,他引:0 下载免费PDF全文
Brigitta U. Mueller Linda L. Lewis Geoffrey J. Yuen Maureen Farley Amy Keller Joseph A. Church Jonathan C. Goldsmith David J. Venzon Marc Rubin Philip A. Pizzo Frank M. Balis 《Antimicrobial agents and chemotherapy》1998,42(12):3187-3192
We studied the pharmacokinetics of intravenously and orally administered lamivudine at six dose levels ranging from 0.5 to 10 mg/kg of body weight in 52 children with human immunodeficiency virus infection. A two-compartment model with first-order elimination from the central compartment was simultaneously fitted to the serum drug concentration-time data obtained after intravenous and oral administration. The maximal concentration at the end of the 1-h intravenous infusion and the area under the concentration-time curve after oral and intravenous administration increased proportionally with the dose. The mean clearance of lamivudine (± standard deviation) in the children was 0.53 ± 0.19 liter/kg/h (229 ± 77 ml/min/m2 of body surface area), and the mean half-lives at the distribution and elimination phases were 0.23 ± 0.18 and 2.2 ± 2.1 h, respectively. Clearance was age dependent when normalized to body weight but age independent when normalized to body surface area. Lamivudine was rapidly absorbed after oral administration, and 66% ± 25% of the oral dose was absorbed. Serum lamivudine concentrations were maintained above 1 μM for ≥8 h of 24 h on the twice daily oral dosing schedule with doses of ≥2 mg/kg. The cerebrospinal fluid drug concentration measured 2 to 4 h after the dose was 12% (range, 0 to 46%) of the simultaneously measured serum drug concentration. A limited-sampling strategy was developed to estimate the area under the concentration-time curve for concentrations in serum at 2 and 6 h. 相似文献
63.
Amy J Bastian Valerie E Kelly Fredy J Revilla Joel S Perlmutter Jonathan W Mink 《Movement disorders》2003,18(9):1000-1007
The purpose of this study was to determine the effects of unilateral versus bilateral subthalamic nucleus (STN) stimulation on quantitative measures of walking and reaching in Parkinson's disease (PD). We used kinematic measures and the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale (subscale III) to evaluate the movement of 6 people with PD who had bilateral STN stimulators implanted for at least 6 months and withheld their anti-parkinson medication for at least 8 hours. Subjects were studied with both stimulators off, one on, and both on. Kinematic data were collected as subjects walked, reached to a target, and were rated using the UPDRS motor subscale. STN stimulation improved walking speed and stride length, with the greatest benefit from bilateral stimulation. Reaching speed was improved by unilateral STN stimulation alone, with no additive effect of bilateral stimulation. UPDRS motor subscale ratings paralleled the kinematic findings. STN stimulation did not restore PD subjects' movements to the level of age-matched controls. Overall, these results provide further evidence that the basal ganglia pathways involved in control of walking and reaching may be distinct. We speculate that basal ganglia may influence walking through bilateral pedunculopontine projections and reaching through ipsilateral thalamocortical projections. Our findings also suggest that maximal improvement of walking requires bilateral rather than unilateral STN stimulation. 相似文献
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Richard J Levy Whitney B Stern Kimberly I Minger Lisa M Montenegro Chitra Ravishankar Jonathan J Rome Susan C Nicolson David R Jobes 《Pediatric critical care medicine》2005,6(6):671-675
BACKGROUND: Mixed venous saturation (S & OV0456;o2) is an important measurement that helps guide the care of critically ill patients. Invasive S & OV0456;o2 assessment in infants and children is often avoided because of the inherent risks. A noninvasive tissue saturation (S to 2) monitor has recently been developed that uses near-infrared spectroscopy to measure oxyhemoglobin saturation in muscle. In adult and animal studies, S to 2 correlated with oxygen delivery and S & OV0456;o2. There has been no evaluation in pediatric patients. OBJECTIVE: To evaluate tissue saturation as a noninvasive measure of mixed venous saturation in children. DESIGN: A prospective observational study. SETTING: Catheterization laboratory in a tertiary care children's medical center. PATIENTS: We studied 98 children (49 without intracardiac mixing and 49 with intracardiac mixing) 相似文献
67.
Hao Wu Colin Webber Carmen Otero Fuentes Robert Bensen Karen Beattie Jonathan D Adachi Xiaoming Xie Farhang Jabbari David R Levy 《Journal l'Association canadienne des radiologistes》2007,58(3):167-175
OBJECTIVES: 1) To assess, with a peripheral magnetic resonance imaging system (pMRI), the prevalence of bony and soft tissue abnormalities in the knee joints of normal subjects, osteoarthritis (OA) patients, and individuals who have suffered an anterior cruciate ligament (ACL) rupture; and 2) to compare the prevalence among groups. METHODS: Magnetic resonance (MR) images of 28 healthy, 32 OA, and 26 ACL damaged knees were acquired with a 1.0-T pMRI system. Two radiologists graded the presence and severity of 9 MR image features: cartilage degeneration, osteophytes, subchondral cyst, bone marrow edema, meniscal abnormality, ligament integrity, loose bodies, popliteal cysts, and joint effusion. RESULTS: Ten of 28 healthy (35.7%), 24 of 26 ACL (92.3%), and all OA knees (100%) showed prevalent cartilage defects; 5 healthy (17.9%), 20 ACL (76.9%), and all OA knees (100%) had osteophytes; and 9 normal (32.1%), 21 ACL (80.8%), and 29 OA knees (90.6%) had meniscal abnormalities. One-half of the knees in the OA group (16 of 32, 50%) had subchondral cysts, and almost one-half had bone marrow edema (15 of 32, 46.9%). These features were not common in the ACL group (7.7%, and 11.5%, respectively) and were not observed in healthy knees. The OA group had the most severe cartilage defects, osteophytes, bone marrow edema, subchondral cysts, and meniscal abnormalities; the ACL group showed more severe cartilage defects, osteophytes, and meniscal abnormalities than did normal subjects. CONCLUSION: The results suggest that knees that have sustained ACL damage have OA-like reatures; most subjects (19 of 26, 73.1%) could be identified as in the early stage of OA. The prominent abnormalities present in ACL-damaged knees are cartilage defects, osteophytes, and meniscal abnormalities. 相似文献
68.
Hydraulic pouches of canine latissimus dorsi. Potential for left ventricular assistance 总被引:1,自引:0,他引:1
J D Mannion R Hammond L W Stephenson 《The Journal of thoracic and cardiovascular surgery》1986,91(4):534-544
We have studied the fatigue rates of hydraulic pouches constructed in the form of a multilayered conical spiral using the latissimus dorsi muscle of 17 beagles. The roles that electrical muscle conditioning and early interruption of collateral blood supply have in the prevention of pouch fatigue were evaluated. The length of time that a pouch could generate flow in a hydraulic test system was measured; afterload was set at 80 mm Hg and preload 24 mm Hg. Pouches (N = 3) fashioned from muscles subject to neither electrical conditioning nor a vascular delay generated an initial flow of 990 +/- 346 ml/min, but could sustain flow for only 2.3, 3.8 and 3.6 minutes. Pouches (N = 5) constructed with electrically unconditioned muscles after a vascular delay (median 3 weeks) demonstrated a variable improvement in fatigue rates (initial flow 826 +/- 265 ml/min; time to no forward flow, 2.5, 7.5, 7.5, 10, and 200 minutes). Four of six pouches that received the benefit of long-term electrical muscle conditioning and a vascular delay (N = 6) were able to generate flow for a 4 hour period, at which time the experiment was terminated (initial flow 478 +/- 204 ml/min; final flow 195 +/- 157 ml/min). After the 4 hour fatigue test was completed, one electrically conditioned pouch was placed in series with the heart and served as a counterpulsator. The initial volume of blood pumped by the muscle pouch was 262 ml/min or 13.8% of cardiac output. After the pouch had contracted at a rate of approximately 45 beats/min for 1 hour, the volume of blood pumped was 178 ml/min, or 11% of cardiac output. In three other animals a pouch was fashioned and then left in situ for a 1 to 3 week period before hydraulic testing. These pouches generated significant initial flows (390 +/- 60 ml/min), which demonstrates the feasibility of further study of permanent pouches. These results suggest that permanent electrical muscle conditioning and perhaps a vascular collateral delay might permit an auxiliary skeletal muscle-powered ventricle to assume a portion of left ventricular function. 相似文献
69.
Cognitive evoked potentials and disorders of recent memory 总被引:1,自引:0,他引:1
P3 potentials evoked by spoken words were recorded from seven patients with disorders of recent memory and seven age-matched controls. Inclusion criteria included a clearly identifiable P3 to pure tone stimuli. Absence or marked decrement of P3 to word stimuli was seen in the patients even though they could perform the word task. The results are consistent with an encoding disorder and failure in elaboration of information processing. 相似文献
70.
Steven JY Wang Claire Cornick Jacqueline O'Dowd Michael A Cawthorne Jonathan R S Arch 《Lipids in health and disease》2007,6(1):2