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Background: The ability of 3D printing using plastics and resins that are magnetic resonance imaging (MRI) compatible provides opportunities to tailor design features to specific imaging needs. In this study an MRI compatible cradle was designed to fit the need for repeatable serial images of mice within a mouse specific low field MRI., Methods: Several designs were reviewed which resulted in an open style stereotaxic cradle to fit within specific bore tolerances and allow maximum flexibility with interchangeable radiofrequency (RF) coils. CAD drawings were generated, cradle was printed and tested with phantom material and animals. Images were analyzed for quality and optimized using the new cradle. Testing with multiple phantoms was done to affirm that material choice did not create unwanted image artifact and to optimize imaging parameters. Once phantom testing was satisfied, mouse imaging began., Results: The 3D printed cradle fit instrument tolerances, accommodated multiple coil configurations and physiological monitoring equipment, and allowed for improved image quality and reproducibility while also reducing overall imaging time and animal safety., Conclusions: The generation of a 3D printed stereotaxic cradle was a low-cost option which functioned well for our laboratory., (© 2021. The Author(s).)

Although trastuzumab has greatly improved the outcome of HER2-positive breast cancer, the emergence of resistance hampers its clinical benefits. Trastuzumab resistance is a multi-factorial consequence predominantly due to presence of cancer stem-like cells (CSCs). AZD1775, a potent anti-cancer agent targeting WEE1 kinase to drive tumor cells with DNA damage to premature mitosis, has previously shown high efficacies when targeting different cancers with a well-tolerated cytotoxic profile, but has not been evaluated in trastuzumab-resistant (TrR) breast cancer. We sought to investigate the effect of AZD1775 on cancer stem-like cell (CSC) properties, apoptosis, cell cycle regulation in TrR breast cancer. Our study for the first time demonstrated that AZD1775 induces apoptosis and arrests TrR cells at G2/M phase. More importantly, AZD1775 effectively targeted CSC properties by suppressing MUC1 expression levels. AZD1775 administration also induced apoptosis in our in-house patient-derived tumor cell line at passage 0, implying its significant clinical relevance. These findings highlight the potential clinical application of AZD1775 in overcoming trastuzumab resistance in breast cancer., (Copyright © 2019 The Author(s). Published by Elsevier B.V. All rights reserved.)

Brown Norway rats (BN, BN/NHsdMcwi) are profoundly resistant to developing acute kidney injury (AKI) following ischemia reperfusion. To help define the genetic basis for this resistance, we used consomic rats, in which individual chromosomes from BN rats were placed into the genetic background of Dahl SS rats (SS, SS/JrHsdMcwi) to determine which chromosomes contain alleles contributing to protection from AKI. The parental strains had dramatically different sensitivity to ischemia reperfusion with plasma creatinine levels following 45 min of ischemia and 24 h reperfusion of 4.1 and 1.3 mg/dl in SS and BN, respectively. No consomic strain showed protection similar to the parental BN strain. Nine consomic strains (SS-7(BN), SS-X(BN), SS-8(BN), SS-4(BN), SS-15(BN), SS-3(BN), SS-10(BN), SS-6(BN), and SS-5(BN)) showed partial protection (plasma creatinine about 2.5-3.0 mg/dl), suggesting that multiple alleles contribute to the severity of AKI. In silico analysis was performed using disease ontology database terms and renal function quantitative trait loci from the Rat Genome Database on the BN chromosomes giving partial protection from AKI. This tactic identified at least 36 candidate genes, with several previously linked to the pathophysiology of AKI. Thus, natural variants of these alleles or yet-to-be identified alleles on these chromosomes provide protection against AKI. These alleles may be potential modulators of AKI in susceptible patient populations.

Frequently, bevacizumab is combined with chemotherapeutics such as irinotecan, motivated by studies showing improved clinical outcomes compared with historical controls. However, no systematic studies have been performed to determine if and how these drugs should be combined for optimal therapeutic response. The purpose of this study was to characterize the temporal combinations of bevacizumab and irinotecan by measuring the contrast-agent enhanced tumor volumes and relative cerebral blood volume using dynamic susceptibility contrast imaging. The studies, performed in the U87 brain tumor model, show a vascular normalization window with bevacizumab monotherapy and are consistent with clinical indications of no additional benefit in the addition of irinotecan to bevacizumab therapy., (Copyright © 2011 Wiley Periodicals, Inc.)

Despite the early promising results with the anti-angiogenic agent, bevacizumab, to prolong time to progression in patients with brain tumors, the optimal dose and drug combinations have not yet been defined. The purpose of this study was to characterize the bevacizumab dose-response relationship for brain tumors by measuring the contrast-agent enhanced tumor volumes and relative cerebral blood volume (rCBV) using dynamic susceptibility contrast (DSC) imaging. The studies, performed in the U87 brain tumor model using doses of bevacizumab ranging from 0 to 10 mg/kg, demonstrate that tumor growth and vascularity are inhibited at all doses used, compared to untreated controls. However, only the maximum dose showed a statistically significant difference in growth rate. Conversely tumor vascularity, as measured with rCBV, was inhibited equally well for all doses used with no clear indication that higher doses are more effective.

Recovery of renal function is a well-characterized feature of models of acute renal failure; however, more recent studies have reported a predisposition to chronic renal disease. This study sought to determine the susceptibility to sodium-dependent hypertension following recovery from ischemic acute renal failure. Following ischemia-reperfusion (I/R) injury, rats were allowed to recover for 35 days on a 0.4% salt diet, then were switched to 4.0% salt diet for an additional 28 days. Blood pressure was significantly increased in postischemic rats switched to high-sodium diet at day 35 (19 +/- 9 mmHg) compared with postischemic rats maintained on low-sodium diet. Plasma renin activity and creatinine clearance were not affected by I/R injury. The ischemic injury combined with transfer to 4.0% salt diet resulted in marked renal hypertrophy characterized by interstitial cellular deposition, tubular dilation, and enhanced rates of albumin excretion. Glomerular structure was altered in post-I/R rats switched to high-sodium diet but not in those maintained on low-sodium diets. When rats were acclimated to high-sodium diet before I/R injury, the early injury was similar to that observed in animals acclimated to low-sodium diet, and these animals progressed rapidly toward chronic kidney disease, as evidenced by advancement of albuminuria. These data suggest that the recovery from acute I/R injury is not complete, compromises Na homeostasis, and predisposes hypertension and secondary renal disease.

In addition to the long-term renal complications, previous studies suggested that after acute renal failure (ARF), rats manifest an increased pressor response to an overnight infusion of ANG II. The present study tested whether recovery from ARF results in alterations in sensitivity to the peripheral vasculature. ARF was induced in Sprague-Dawley rats by 45 min of bilateral renal ischemia and reperfusion. Animals were allowed to recover renal structure and function for 5-8 wk, after which the acute pressor responses to ANG II were evaluated either in vivo in in situ skeletal muscle arterioles or in isolated gracilis muscle arteries in vitro. Baseline arterial pressure was not different in ARF rats vs. sham-operated controls, although ARF rats exhibited an enhanced pressor response to bolus ANG II infusion compared with control rats. Steady-state plasma ANG II concentration and plasma renin activity were similar between ARF and control rats. Constrictor reactivity of in situ cremasteric arterioles from ARF rats was enhanced in response to increasing concentrations of ANG II; however, no difference was observed in arteriolar responses to elevated PO2, norepinephrine, acetylcholine, or sodium nitroprusside. Isolated gracilis muscle arteries from ARF rats also showed increased vasoconstriction in response to ANG II but not norepinephrine. In conclusion, recovery from ischemic ARF is not associated with hypertension but is associated with increased arteriolar constrictor reactivity to ANG II. Although the mechanisms of this altered responsiveness are unclear, such changes may relate, in part, to cardiovascular complications in patients with ARF and/or after renal transplant.

Transforming growth factor (TGF)-beta1 and a number of TGF-beta-responsive genes are transiently enhanced following induction of ischemic acute renal failure (ARF) in the rat. The mRNA and protein expression of TGF-beta receptors were analyzed in postischemic rat kidneys by ribonuclease protection, in situ hybridization, and immunohistochemistry. TGF-betaRI and -RII were enhanced within 3 days of ischemia-reperfusion (I/R) injury and remained elevated for up 7 days post-I/R; TGF-beta receptor expression was localized primarily in regenerating tubules within the outer medulla. A neutralizing TGF-beta antibody exacerbated cellular proliferation observed on day 3 postischemia but had no effect on day 1 or 2. TGF-beta antibody treatment had no measurable effect on loss of renal function or the restoration of renal function during the recovery response for up to 35 days postsurgery. However, ischemic injury resulted in modest renal hypertrophy that is due, in part, to in an increase in the number of interstitial cells in the postischemic kidney. Immunohistochemistry showed that several of these cells stained positively for the fibroblast-specific marker, S100A4 positive. Anti-TGF-beta treatment substantially attenuated the renal hypertrophy, interstitial cellularity, and S100A4-positive cells present at 35 days post-I/R. Finally, TGF-beta immunoneutralization attenuated the loss of renal vascular density following recovery from I/R injury. These data suggest that the TGF-beta/TbetaR system is enhanced in the postischemic kidney. However, the current study failed to identify a prominent role for this system in the repair of proximal tubules following ARF. In contrast, the activation of this system may play an important role in the long-term structure of the postischemic kidney by influencing microvascular structure and interstitial cellularity.

Ischemic acute renal failure (ARF) results in the permanent loss of peritubular capillaries and predisposes the progression of chronic renal failure. The present study was undertaken to determine whether renal hypoxia, which may represent an important mediator in disease progression, is persistently exacerbated after recovery from ARF. Rats were subjected to ischemia-reperfusion injury and allowed to recover for 5 or 20 wk. Immunohistochemistry of the hypoxia-sensitive marker 2-pimonidizole at 5 wk revealed an overall increase in incorporation in the outer medullary region after recovery from ARF compared with sham-operated controls. Unilateral nephrectomy, in combination with ischemia-reperfusion injury resulted in greater 2-pimonidizole staining than that observed in the bilateral injury model. In addition, in the unilateral ischemia-nephrectomy model, proteinuria, interstitial fibrosis, and renal functional loss developed significantly faster than in the bilateral model of ARF when animals were allowed to recover for 20 wk. l-Arginine in the drinking water ( approximately 0.5 g/day) increased total renal blood flow approximately 30%, decreased pimonidizole staining, and attenuated manifestations of chronic renal disease. These data suggest that a reduction in the peritubular capillary density after ARF results in a persistent reduction in renal Po(2) and that hypoxia may play an important role in progression of chronic renal disease after ARF.

Objective: The aim of this study was to investigate the second-generation photosensitizer benzoporphyrin derivative (BPD) and a novel light source applicator based on light-emitting diode (LED) technology for photodynamic therapy (PDT) of brain tumors., Methods: We used a canine model to investigate normal brain stem toxicity. Twenty-one canines underwent posterior fossa craniectomies followed by PDT with BPD. These animals were compared to light only and BPD control. In addition, we investigated the ability of BPD and LED to cause inhibition of cell growth in canine glioma and human glioma cell lines, in vitro. The biodistribution of BPD labeled with 111In-BPD in mice with subcutaneous and intracerebral gliomas and canines with brain tumors was studied., Results: The in vivo canine study resulted in a maximal tolerated dose of 0.75 mg/kg of BPD and 100 J/cm(2) of LED light for normal brain tissue. The in vitro study demonstrated 50% growth inhibition for canine and human glioma cell lines of 10 and 4 ng/ml, respectively. The mucine study using 111In-BPD showed a tumor to normal tissue ratio of 12:1 for intracerebral tumors and 3.3:1 for subcutaneous tumors. Nuclear scans of canines with brain tumors showed uptake into tumors to be maximal from 3 to 5 h., Conclusion: Our study supports that BPD and LED light sources when used at appropriate drug and light doses limit normal brain tissue toxicity at doses that can cause significant glioma cell toxicity in vitro. In addition, there is higher BPD uptake in brain tumors as compared to normal brain in a mouse glioma model. These findings make BPD a potential new-generation photosensitizer for the treatment of childhood posterior fossa tumors as well as other malignant cerebral pathology.