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111.
A new rhesus monkey model with two intraventricular catheter systems was developed to examine the pharmacokinetics and neurotoxicity of chemotherapeutic agents administered by continuous intraventricular infusion. A lateral ventricular catheter system implanted in the lateral ventricle and attached to a subcutaneous access port on the animal's back is used for infusion of drugs into the ventricle. A Pudenz catheter implanted in the fourth ventricle and connected to a subcutaneous Ommaya reservoir permits repetitive CSF sampling in unanesthetized animals. The model was evaluated in five animals for over 12 months for catheter patency, surgical complications, and utility in studying the pharmacokinetics of continuous intraventricular infusion of methotrexate. There were no perioperative complications. Three of the five monkeys maintained both systems successfully. The other two animals developed staphylococcal ventriculitis, one at 7 days as a result of manipulation of the incision by the animal leading to cellulitis around the catheter site and subsequent ventriculitis, the other at 5 months. Both animals were treated successfully with antibiotics and catheter removal. An infusion of 0.05 mg of methotrexate over 24 hours maintained ventricular drug concentrations of 1 mol/L without evidence of neurotoxicity. This new model has applications both for the development of continuous intraventricular infusion as a therapeutic approach for the treatment of meningeal cancers in humans and as a research tool to study the distribution and elimination of drugs from the CSF. 相似文献
112.
Cynthia M Lester McCully John Bacher Rhonda P MacAllister Emilie A Steffen-Smith Kadharbatcha Saleem Marvin L Thomas rd Rafael Cruz Katherine E Warren 《Comparative medicine》2015,65(1):77-82
Rapid, serial, and humane collection of cerebrospinal fluid (CSF) in nonhuman primates (NHP) is an essential element of numerous research studies and is currently accomplished via two different models. The CSF reservoir model (FR) combines a catheter in the 4th ventricle with a flexible silastic reservoir to permit circulating CSF flow. The CSF lateral port model (LP) consists of a lateral ventricular catheter and an IV port that provides static access to CSF and volume restrictions on sample collection. The FR model is associated with an intensive, prolonged recovery and frequent postsurgical hydrocephalus and nonpatency, whereas the LP model is associated with an easier recovery. To maximize the advantages of both systems, we developed the CSF lateral reservoir model (LR), which combines the beneficial features of the 2 previous models but avoids their limitations by using a reservoir for circulating CSF flow combined with catheter placement in the lateral ventricle. Nine adult male rhesus monkeys were utilized in this study. Pre-surgical MRI was performed to determine the coordinates of the lateral ventricle and location of choroid plexus (CP). The coordinates were determined to avoid the CP and major blood vessels. The predetermined coordinates were 100% accurate, according to MRI validation. The LR system functioned successfully in 67% of cases for 221 d, and 44% remain functional at 426 to 510 d postoperatively. Compared with established models, our LR model markedly reduced postoperative complications and recovery time. Development of the LR model was successful in rhesus macaques and is a useful alternative to the FR and LP methods of CSF collection from nonhuman primates.Abbreviations: CP, choroid plexus; FR, CSF 4th ventricular reservoir model; LP, CSF lateral port model; LR, CSF lateral reservoir model; SER, successful establishment rateSerial ventricular CSF sampling in NHP is a frequent and critical requirement for a wide variety of studies and is predominantly accomplished by using either of 2 models. The 4th ventricle (FR) model, previously referred to as an Ommaya reservoir,6 and lateral port (LP) models2 are closed, indwelling, subcutaneous systems that allow for serial, rapid, and humane collection of CSF, as well as intraventricular drug administration, in unanesthetized and restrained NHP.The FR model (Figure 1 A) consists of a catheter that is placed in the 4th ventricle and attached to a silastic reservoir that is implanted subcutaneously over the occipital bone. The silastic reservoir is depressed repetitively prior to and after sampling to circulate the CSF throughout the ventricles and catheter system to provide an unbiased sample without volume loss to dead space. The reservoir is accessed percutaneously to obtain a CSF sample via aspiration or to administer drug. The FR model initially was developed in 19776 and continues to be used for pharmacokinetic studies. This system continues to demonstrate a low rate of successful establishment, but once established, the FR model remains patent for prolonged periods without evidence of neurologic sequelae or bleeding from the choroid plexus (CP) in rhesus macaques. The decreased establishment rate of this model is attributed, at least in part, to postsurgical development of hydrocephalus, given that the catheter, which is routed through the aqueduct of Magendie to the 4th ventricle, can obstruct the flow of CSF. In addition, maintaining catheter patency is problematic due to CP bleeding during the recovery period. Postsurgical care and recovery after creating the FR are extensive, frequently requiring prolonged analgesics and steroid administration, with many days needed for complete recovery.Open in a separate windowFigure 1.Evolution of CSF ventricular models, with flow dynamics. (A) Sagittal diagram of original FR (Ommaya) model, with placement in the 4th ventricle. Developed in 1977. Arrows indicate the circulating flow of CSF. (B) Original LP model, with catheter placement in the lateral ventricle and attachment to an IV access port. Developed in 1990. Arrows indicate the static, unidirectional flow of CSF. (C) The LR model, a composite of the 2 earlier CSF models. Arrows indicate the circulating flow of CSF.The LP model (Figure 1 B) consists of a catheter that is implanted in the lateral ventricle and attached to a subcutaneous intravenous access port. The port is accessed percutaneously to obtain the CSF sample or to administer a drug. The LP is a static model, because the CSF is not circulated or mixed through the ventricles, and CSF is obtained via unidirectional flow. The LP model was developed in 1990 for intrathecal drug administration3 and has been used subsequently for CSF collection4 by several investigators. CSF sampling with the LP model is restrictive: the volume of the system (that is, the dead space) must be removed at each collection to obtain an unbiased sample, collection is accomplished via gravitational flow and not aspiration, and the collection frequency is dependent on the rate of CSF replacement. In addition, the potential for sample contamination from blood due to CP bleeding remains problematic for the duration of LP implantation. However, the use of the lateral ventricle avoids the postsurgical complication of hydrocephalus. This system demonstrated a high rate of successful establishment with a reduction in the necessary analgesic and steroid administration as well as days to complete recovery, as compared with the FR model. Analysis of our clinical records from 2003 to 2013 revealed a successful establishment rate (SER) of 39% for the FR model; 33% of these systems remained functional for 3 to 7.5 y (Successful establishment rate (%)
Duration
4 mo 1 y or more No. of days No. of months No. of years LP (n = 11) 91 82 1075 35.3 2.9 LR (n = 9) 67 44 292.9 9.6 0.8 FR (n = 18) 39 33 637.6 21.0 1.8