Aspergillus galactomannan antigenemia is an accepted tool for the diagnosis of invasive pulmonary aspergillosis (IPA) in neutropenic patients. Little is known, however, about the utility of this biomarker to assess the efficacy of antifungal therapies. The pharmacokinetics (PK) and pharmacodynamics (PD) of posaconazole in treatment and prophylaxis were investigated in the persistently neutropenic rabbit model of Aspergillus fumigatus IPA at doses between 2 and 20 mg/kg per day.

Hematogenous Candida meningoencephalitis (HCME) is a life-threatening complication of neonates and immunocompromised children. Amphotericin B (AmB) shows poor permeability and low cerebrospinal fluid (CSF) concentrations, but is effective in treatment of HCME. In order to better understand the mechanism of CNS penetration of AmB, we hypothesized that AmB may achieve focally higher concentrations in infected CNS lesions. An in vitro BBB model was serially infected with C. albicans. Liposomal AmB (LAMB) or deoxycholate AmB (DAMB) at 5 μg/ml were then provided, vascular and CNS compartments were sampled 4h later. For in vivo correlation, rabbits with experimental HCME received a single dose of DAMB 1 mg/kg or LAMB 5 mg/kg, and were euthanized after 1, 3, 6 and 24h. Evans blue solution (2%) 2 ml/kg administered IV one hour prior to euthanasia stained infected regions of tissue but not histologically normal areas. AmB concentrations in stained and unstained tissue regions were measured using UPLC. For selected rabbits, MRI scans performed on days 1-7 postinoculation were acquired before and after IV bolus Gd-DTPA at 15min intervals through 2h post-injection. The greatest degree of penetration of DAMB and LAMB through the in vitro BBB occurred after 24h of exposure (P=0.0022). In vivo the concentrations of LAMB and DAMB in brain abscesses were 4.35±0.59 and 3.14±0.89-times higher vs. normal tissue (P≤0.019). MRI scans demonstrated that Gd-DTPA accumulated in infected areas with disrupted BBB. Localized BBB disruption in HCME allows high concentrations of AmB within infected tissues, despite the presence of low CSF concentrations.

Biomedical translational research frequently incorporates collection of CSF from NHP, because CSF drug levels are used as a surrogate for CNS tissue penetration in pharmacokinetic and dynamic studies. Surgical placement of a CNS ventricular catheter reservoir for CSF collection is an intensive model to create and maintain and thus may not be feasible or practical for short-term studies. Furthermore, previous NHP lumbar port models require laminectomy for catheter placement. The new model uses a minimally invasive technique for percutaneous placement of a lumbar catheter to create a closed, subcutaneous system for effective, repeated CSF sample collection. None of the rhesus macaques (Macaca mulatta; n = 10) implanted with our minimally invasive lumbar port (MILP) system experienced neurologic deficits, postoperative infection of the surgical site, or skin erosion around the port throughout the 21.7-mo study. Functional MILP systems were maintained in 70% of the macaques, with multiple, high-quality, 0.5- to 1.0-mL samples of CSF collected for an average of 3 mo by using aspiration or gravitational flow. Among these macaques, 57% had continuous functionality for a mean of 19.2 mo; 50% of the cohort required surgical repair for port repositioning and replacement during the study. The MILP was unsuccessful in 2 macaques, at an average of 9.5 d after surgery. Nonpatency in these animals was attributed to the position of the lumbar catheter. The MILP system is an appropriate replacement for temporary catheterization and previous models requiring laminectomy and is a short-term alternative for ventricular CSF collection systems in NHP.

Animal modeling of human disease has a long history but remains controversial especially when using a sensitive species. Despite these controversies, in a stroke research, a nonprimate model has been recognized as a most successful and useful for developing new treatments. Among stroke models, a nonhuman primate model of delayed cerebral vasospasm after subarachnoid blood clot placement has a very unique position as it revealed important pathomechanisms and led to development of several crucial clinical trials. In 1989, we adopted this model to study pathophysiology and develop a treatment against delayed cerebral vasospasm after intracranial aneurysm rupture (aSAH). In this chapter, we presented detailed descriptions of the animal treatment according to the National Institutes of Health guidance, techniques of anesthesia, cerebral arteriography, suboccipital puncture for cerebrospinal fluid collection, a surgical clot placement along the middle cerebral artery as well as postoperative care, euthanasia, and autopsy. Moreover, to accommodate the recent clinical findings, strongly suggesting a limited role of delayed cerebral vasospasm on the outcome of aSAH, we proposed a modification of the model, which addressed some mechanisms of ultra and early damage to the brain evoked by an intracranial aneurysm rupture.

Purpose: To evaluate the effect of embolic diameter on achievement of hypoxia after embolization in an animal model of liver tumors.Materials and Methods: Inoculation of VX2 tumors in the left liver lobe was performed successfully in 12 New Zealand white rabbits weighing 3.7 kg +/- 0.5 (mean +/- SD). Tumors were deemed eligible for oxygen measurements when the maximum transverse diameter measured 15 mm or more by ultrasound examination. Direct monitoring of oxygenation of implanted rabbit hepatic VX2 tumors was performed with a fiberoptic electrode during and after transarterial embolization of the proper hepatic artery to angiographic flow stasis with microspheres measuring 70-150 mu m, 100-300 mu m, or 300-500 mu m in diameter.Results: Failure to achieve tumor hypoxia as defined despite angiographic flow stasis was observed in 10 of 11 animals. Embolization microsphere size effect failed to demonstrate a significant trend on hypoxia outcome among the diameters tested, and pair-wise comparisons of different embolic diameter treatment groups showed no difference in hypoxia outcome. All microsphere diameters tested resulted in similar absolute reduction (24.3 mm Hg +/- 18.3, 29.1 mm Hg +/- 1.8, and 19.9 mm Hg +/- 9.3, P =.66) and percentage decrease in oxygen (56.0 mm Hg +/- 23.9, 56.0 mm Hg +/- 6.4, and 35.8 mm Hg +/- 20.6, P =.65). Pair-wise comparisons for percent tumor area occupied by embolic agents showed a significantly reduced fraction for 300-500 pm diameters compared with 70-150 pm diameters (P <.05).Conclusions: In the rabbit VX2 liver tumor model, three tested microsphere diameters failed to cause tumor hypoxia as measured by a fiberoptic probe sensor according to the adopted hypoxia defmitions.

Galactomannan and (1→3)-β-D-glucan are useful biomarkers of invasive pulmonary aspergillosis (IPA). However, the effects of immunosuppression on levels of galactomannan or (1→3)-β-D-glucan in IPA are not well understood or quantified. We therefore studied the simultaneous levels of galactomannan and (1→3)-β-D-glucan in two rabbit models of experimental IPA: (1) AraC-induced neutropenia in untreated (UC-AraC) and liposomal amphotericin B-treated (LAMB-AraC) rabbits; and (2) nonneutropenic cyclosporine-methylprednisolone immunosuppression in untreated (UC-CsA+M) and LAMB-treated (LAMB-CsA+M) rabbits. Simultaneous levels of galactomannan and (1→3)-β-D-glucan were determined in bronchoalveolar lavage (BAL) fluid and serial serum specimens and correlated with pulmonary host response. Serum galactomannan index (GMI) and (1→3)-β-D-glucan concentration-time-curves were higher in UC-AraC vs. UC-CsA+M (Mann-Whitney U-test, P < .05). Serum galactomannan and (1→3)-β-D-glucan in treatment groups demonstrated therapeutic responses with similarly lower levels in comparison to UC (P < .01) in both models. Host differences did not affect BAL fluid GMI or (1→3)-β-D-glucan but did affect galactomannan and (1→3)-β-D-glucan levels in serum. The higher serum GMI and (1→3)-β-D-glucan concentration-time-curves in UC-AraC correlated with extensive pulmonary infiltration by angioinvasive hyphae and minimal inflammation, while the lower concentration-time-curves in UC-CsA+M were associated with shorter and fewer hyphae in lung tissue and an intensive neutrophil response to Aspergillus hyphae. Thus, serum levels of galactomannan and (1→3)-β-D-glucan in IPA depended upon immunosuppression, which also affected severity of infection and hyphal morphology, while BAL fluid galactomannan and (1→3)-β-D-glucan were sensitive biomarkers not affected by host response.

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.

Purpose: To quantify changes in tumor microvascular (<1 mm) perfusion relative to commonly used angiographic endpoints.Materials and Methods: Rabbit Vx2 liver tumors were embolized with 100300-mu m LC Bead particles to endpoints of substasis or complete stasis (controls were not embolized). Microvascular perfusion wars evaluated by delivering two,different fluorophore-conjugated perfusion markers (ie, lectins) through the catheter before embolization and 5 min after reaching the desired angiographic endpoint. Tumor microvasculature was labeled with an anti-CD31 antibody and analyzed with fluorescence microscopy for perfusion marker overlap/mismatch. Data were analyzed by analysis of variance and post hoc test (n = 3-5 per group; 18 total).Results: Mean microvascular density was 70 vessels/mm(2) +/- 17 (standard error of the mean), and 81% 1 of microvasculature (ie, CD31(+) structures) was functionally perfused within viable Vx2 tumor regions. Embolization to the extent of substasis eliminated perfusion in 37% +/- 9 of perfused microvessels P > .05 vs baseline), whereas embolization to the extent of angiographic stasis eliminated perfusion in 56% +/- 8 of perfused microvessels. Persistent microvascular perfusion following embolization was predominantly found in the tumor periphery, adjacent to normal tissue. Newly perfused microvasculatute was evident following embolization to substasis but not when embolization was performed to complete angiographic stasis.Conclusions: Nearly half of tumor microvasculature remained patent despite embolization to complete angiographic stasis. The observed preservation of tumor microvasculature perfusion with angiographic endpoints of substasis and stasis may have implications for tumor response to embolothetapy.

Aneurismal subarachnoid hemorrhage (SAH) is relatively rare form of hemorrhagic stroke, which produces significant social and medical challenges. As it affects people in their high productivity age and leaves 50 % of them dead and almost 70 % of survivors disabled, many of them severely, the reasons of such a dismal outcome have been intensively researched all over the world. Nevertheless, despite more than a half a century of clinical and scientific effort and dramatic improvement of surgical repair of aneurysms, the causes of poor outcome remain enigmatic. Introduction of numerous in vitro and in vivo models to study the unleashed by SAH mechanisms that injured the brain significantly advanced our understanding of biology of cerebral vessels, brain responses to intracranial pressure changes, and the presence of blood clot in subarachnoid space. One of the most important animal models that significantly contributed to those advances has been a non-human primate model introduced at the Bryce Weir laboratory in the University of Alberta, Canada, in 1984. Since then, this model, with some modifications, has been successfully used in several animal laboratories in the USA, Canada, and Japan. We present the model characteristics and describe in details medical, surgical, imagining techniques that we have used at the Surgical Neurology Branch of the National Institute of Neurological Disorders and Stroke from 1989.

Pediatric diffuse intrinsic pontine gliomas are aggressive brainstem tumors that fail to respond to treatment. We hypothesize that the protective features of the pons may hinder chemotherapeutic agents from entering pontine tissue compared with cortical brain tissue. To test this hypothesis, we developed a unique nonhuman primate model using microdialysis, a continuous in vivo extracellular sampling technique, to compare drug exposure concurrently in pontine tissue, cortical tissue, CSF, and plasma after intravenous administration of chemotherapeutic agents. The surgical coordinates and approach for microdialysis cannula-probe placement were determined in 5 adult male rhesus monkeys (Macaca mulatta) by using MRI. Microdialysis cannulas-probes were implanted stereotactically in the brain, retrodialysis was performed to measure relative recovery, and a 1-h intravenous infusion of temozolomide was administered. Continuous microdialysis samples were collected from the pons and cortex over 4 h with concurrent serial plasma and CSF samples. Postsurgical verification of microdialysis cannula-probe placement was obtained via MRI in 3 macaques and by gross pathology in all 5 animals. The MRI-determined coordinates and surgical methodologies resulted in accurate microdialysis probe placement in the pons and cortex in 4 of the 5 macaques. Histologic examination from these 4 animals revealed negligible tissue damage to the pontine and cortical tissue from microdialysis. One macaque was maintained for 8 wk and had no deficits attributed to the procedure. This animal model allows for the determination of differences in CNS penetration of chemotherapeutic agents in the pons, cortex, and CSF after systemic drug administration.

Members of the order Mucorales are emerging invasive molds that cause infections in immunocompromised patients. However, little is known about the relation between different species of Mucorales and their virulence in invasive pulmonary mucormycosis. Based upon our earlier epidemiological studies, we hypothesized that Cunninghamella bertholletiae would demonstrate increased virulence. Therefore, we studied the relative virulence of C. bertholletiae (CB), Rhizopus oryzae (RO), R. microsporus (RM), and Mucor circinelloides (MC) in experimental invasive pulmonary mucormycosis in persistently neutropenic rabbits in relation to the fungi in vitro sporangiospore germination rate and hyphal metabolic activity. Rabbits infected with CB demonstrated (1) higher lung weights in comparison to RM (P ≤ 0.05), RO and MC (P ≤ 0.001), (2) pulmonary infarcts in comparison to RO and MC (P ≤ 0.001), (3) tissue fungal burden (CFU/g) vs. MC (P ≤ 0.001), and (4) the lowest survival of 0% (0/18), in comparison to 16% (3/18, P ≤ 0.01) of RM, 81% (21/26) of RO, and 83% (15/18) of MC-infected rabbits (P ≤ 0.001). Serum PCR concentration-time-curve showed the greatest amplitude for CB. Virulence correlated directly with sporangiospore germination rate at 4 h among species, i.e., CB (67-85%) > RM (14-56%) > RO (4-30%) > MC (0%), and hyphal metabolic activity, i.e., CB (1.22-1.51) > MC (0.54-0.64) = RM (0.38-0.41) = RO (0.37-0.59). C. bertholletiae was significantly more virulent in experimental invasive pulmonary mucormycosis than R. microsporus, R. oryzae, and M. circinelloides. In vivo virulence correlated with species-dependent differences of in vitro germination rate and hyphal metabolic activity.

To determine the dymanic response in oxygen tension in rabbit hepatic Vx2 tumors as a consequence of arterial embolization using direct needle-based measurements. Catheterization of rabbit (2-4 kg) proper hepatic artery was achieved via femoral artery cannulation. A OxyliteTM probe (Oxford Optronix, Oxford, UK) was percutaneously placed into an intrahepatic Vx2 tumor (≥ 1.5cm) under sonographic guidance using a coaxial technique. Baseline oxygen level was established by observing a stable value (<10% variation) for at least ten minutes after probe placement. Embolization was then performed with 0.5 cc aliquots of 1:20 v/v dilute solutions of 100-300μm or 70-150μm diameter LC Beads® (Biocompatibles UK Ltd, Farnham, UK), or 40μm in diameter Embozene® (CeloNova Biosciences, San Antonio TX) delivered every five minutes until flow stasis was achieved. Tumor oxygen level was recorded in continuous fashion (every 5 sec) before, during, and after embolization. Hypoxia was defined as a measured oxygen pressure of ≤5mm Hg. 5/9 intrahepatic tumors had a hypervascular appearance at arteriography. Animals were randomly assigned to receive 100-300μm (n= 2), 70-150μm (n=4), or 40μm (n=3) beads. Beads were injected in the proper hepatic artery in all cases except one (common hepatic, 70-150μm). In 43% of instances, a decline of >5% of tumor oxygen tension was not achieved following administration of individual bead aliquots. Failure to achieve tumor hypoxia despite hepatic artery flow stasis was observed in 4/9 animals. A trend toward achieving hypoxia with smaller bead diameter was observed (40 μm: 3/3, 70-150μm: 2/4, 100-300μm: 0/2). Hypervascular appearance on angiography does not seem to predict for oxygenation response to embolization. Achieveing angiographic flow stasis in rabbit hepatic Vx2 tumors does not correlate with tumor hypoxia. Bead diameter may have an impact on post embolization tumor oxygenation. Further work is required to elucidate potential compensatory mechanisms such as collateral flow or reperfusion phenomena.

Abstract Background: We developed a nonhuman primate model using rhesus macaques (Macaca mulatta) to compare drug exposure in cortical brain, pontine tissue, and cerebrospinal fluid (CSF) during systemic administration of chemotherapeutic agents by microdialysis (MD), a continuous in vivo extracellular sampling technique. Pediatric diffuse intrinsic pontine gliomas are aggressive brainstem tumors that respond minimally to chemotherapy. We hypothesize that, because of its role in maintaining basic life-sustaining functions, the protective features of the pons, including the blood brain barrier and the blood-cerebrospinal fluid barrier, may further limit antitumor agents from entering the pons compared to cortical brain tissue. Methods: The coordinates and surgical approach for probe placement were determined using 3T MRI (Philips Healthcare, Best Netherlands) and OsiriX imaging software (v 3.9.4) in 4 adult male rhesus macaques (Macaca mulatta). Custom MD cannulas and probes (CMA, Solna, Sweden) were stereotactically implanted in the brain. The pontine MD cannula (34 mm) was implanted superior to the pons, and the MD probe (34 mm shaft plus 8 mm membrane) was then lowered through the cannula, into the pons. The cortical MD cannula (10 mm) was implanted in frontal cortex and a MD probe (10 mm shaft plus 8 mm membrane) was lowered through the cannula. The MD probe inlet/outlet capillaries were connected to a MD infusion pump (CMA 106, flow rate 0.3 µL/min). Retrodialysis was performed to assess in vivo recovery. A systemic intravenous (IV) drug infusion of temozolomide was then administered over 1hr. Single continuous MD samples were collected from both the pons and cortex over 4 hours with concurrent serial plasma and CSF samples (via a subarachnoid or lumbar catheter). Post-surgical MRI verification of MD probe placement was obtained in 2 of 4 animals. Verification of probe placement was obtained via gross pathology and histology in all 4 animals. Results: MRI-determined coordinates and surgical approach for MD probe placement and sample collection in the pons and cerebral cortex was successful in 3 of 4 animals. Surgical monitoring for heart and respiration rates, ETCO2 and SPO2 remained normal in all animals during probe placement and sample collection. Conclusions: MRI-determined coordinates and surgical methodologies resulted in accurate placement of a MD probe in the pons and cerebral cortex of a rhesus macaque allowing for MD sampling from these sites, in conjunction with CSF and plasma sampling, following systemic drug administration. This new animal model allows for the determination of differences in penetration of chemotherapeutic agents in pons, cerebrum, and CSF following systemic drug administration. Additionally, this model provides the foundation for a subcutaneous, semi-permanent, closed system for CNS MD probe placement and continuous sampling in rhesus macaques. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3789. doi:1538-7445.AM2012-3789

ABSTRACT Diagnosis of invasive pulmonary aspergillosis (IPA) remains a major challenge to clinical microbiology laboratories. We developed rapid and sensitive quantitative PCR (qPCR) assays for genus- and species-specific identification of Aspergillus infections by use of TaqMan technology. In order to validate these assays and understand their potential diagnostic utility, we then performed a blinded study of bronchoalveolar lavage (BAL) fluid specimens from well-characterized models of IPA with the four medically important species. A set of real-time qPCR primers and probes was developed by utilizing unique ITS1 regions for genus- and species-specific detection of the four most common medically important Aspergillus species ( Aspergillus fumigatus , A. flavus , A. niger , and A. terreus ). Pan- Aspergillus and species-specific qPCRs with BAL fluid were more sensitive than culture for detection of IPA caused by A. fumigatus in untreated ( P < 0.0007) and treated ( P ≤ 0.008) animals, respectively. For infections caused by A. terreus and A. niger , culture and PCR amplification from BAL fluid yielded similar sensitivities for untreated and treated animals. Pan- Aspergillus PCR was more sensitive than culture for detection of A. flavus in treated animals ( P = 0.002). BAL fluid pan- Aspergillus and species-specific PCRs were comparable in sensitivity to BAL fluid galactomannan (GM) assay. The copy numbers from the qPCR assays correlated with quantitative cultures to determine the pulmonary residual fungal burdens in lung tissue. Pan- Aspergillus and species-specific qPCR assays may improve the rapid and accurate identification of IPA in immunocompromised patients.

We demonstrated that sodium gluconate was the factor causing false-positive galactomannan (GM) antigenemia of Plasma-Lyte hydration solution. Infusion of sodium gluconate-containing solution but not gluconate-free Plasma-Lyte resulted in positive serum GM antigenemia. Serum GM concentrations also correlated with the volume and in vitro concentrations of GM within gluconate-containing solutions of infused Plasma-Lyte.

Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer 11 Institute, NIH, Bethesda, MD, 12 Transplantation-Oncology Infectious Diseases Program, Division of Infectious 13 Diseases, Weill Cornell Medical College of Cornell University, New York, NY, 14 New York Presbyterian Hospital, New York, NY, 15 Viracor-IBT Laboratories, Lee’s Summit, MO, 16 Laboratory Animal Sciences Program, SAIC-Frederick, Inc., Bethesda, MD, 17 Surgery Service, Veterinary Resources Program, Office of Research Services, National 18 Institutes of Health, Bethesda, MD, 19 Physicians Reference Laboratories, Overland Park, KS 20 21

Acute invasive pulmonary aspergillosis is a rapidly progressive and frequently lethal infection. Rela- tively little is known about early events in the pathogenesis and relationship between the cell wall biomarkers galactomannan and (1 3 3)- (cid:1) - D -glucan. The consequences of delayed antifungal therapy are also poorly defined. A persistently neutropenic rabbit model of invasive pulmonary aspergillosis was used to describe the histopathology of early invasive pulmonary aspergillosis and the kinetics of galactomannan and (1 3 3)- (cid:1) - D -glucan. The time course of both molecules was mathematically modeled by using a population methodology, and Monte Carlo simulations were performed. The effect of progressive delay in the administration of amphotericin B deoxycholate 1 mg/kg at 24, 48, 72, and 96 h postinoculation on fungal burden, lung weight, pulmonary infarct score, and survival was determined. Histopathology showed phagocytosis of conidia by pulmonary alveolar macrophages at 4 h postinoculation. At 12 to 24 h, there was a progressive focal inflammatory response with conidial germination and hyphal extension. Subse- quently, hyphae invaded into the contiguous lung. Galactomannan and (1 3 3)- (cid:1) - D -glucan had similar trajectories, and both exhibited considerable interindividual variability, which was reflected in Monte Carlo simulations. Concentrations of both molecules began to rise <24 h postinoculation before pulmonary hemorrhagic infarction was present. Delays of 72 and 96 h in the administration of amphotericin B resulted in fungal burdens and lung weights that were indistinguishable from those of controls, respectively. Galactomannan and (1 3 3)- (cid:1) - D -glucan have similar kinetics and are comparable biomarkers of early invasive pulmonary aspergillosis. Antifungal treatment at > 48 h postinoculation is associated with suboptimal therapeutic outcomes. Bayesian estimates for the parameter values that described the concentration-time profile for individual rabbits were obtained. Monte Carlo simulation was then used to further explore the implications of the experimental data and the mathematical model. These simulations were performed using the pharmacokinetic program ADAPT II (6). The estimates for central tendency for each of the parameters [mean and median for (1 3 3)- (cid:1) - D glucan and galactomannan, respectively], and their variances were inserted into subroutine PRIOR of ADAPT II (6). A series of 9,999-rabbit simulations were performed. Both normal and log-normal parameter distributions were evaluated and assessed for their ability to recapitulate the initial parameter values and their distributions. The trajectories for the 2.5th, 50th, and 97.5th percentiles for the simulated population were plotted to provide a further assessment of the extent of interindividual variability. The survival of rabbits treated after various delays was assessed by using a Kaplan-Meier model implemented within the statistical program SYSTAT ver- sion 11. Rabbits that survived to the end of the study were right-censored. The correlation between paired concentration and the AUCs for galactomannan and (1 3 3)- (cid:1) - D -glucan was assessed by using Spearman’s coefficient. Analysis of variance was used to compare the log 10 CFU/g, infarct scores, and lung weights between the various treatment delay groups. A Bonferroni correction was used to adjust for multiple comparisons.