CTNI-23. PRELIMINARY SAFETY AND PHARMACOKINETICS DATA FOR A PHASE 1B TRIAL OF TELAGLENASTAT IN COMBINATION WITH RADIATION THERAPY AND TEMOZOLOMIDE IN PATIENTS WITH IDH-MUTANT GRADE 2/3 ASTROCYTOMA (NCI-10218)

IDH mutant gliomas depend on glutaminase for glutamate/glutathione generation from glutamine because R-2-hydroxyglutarate inhibits branched chain amino acid transaminase mediated glutamate biosynthesis. Telaglenastat (CB-839 HCl) is a potent glutaminase-1 specific inhibitor which depletes tumor glutamate in orthotopic IDH mutant glioma PDX models and extends survival in these orthotopic models when added to radiation/temozolomide. NCI-10218 (NCT03528642) is a phase I clinical trial investigating the safety and tolerability of telaglenastat administered orally concurrently with standard doses of radiation (50.4 Gy, grade 2; 59.4 Gy, grade 3) and temozolomide (75 mg/m2 orally daily) in patients (age 16+) with previously untreated IDH mutant grade 2/3 astrocytoma. Telaglenastat dose was escalated in cohorts (400-800 mg twice daily) based on a standard 3 + 3 design to determine the recommended phase 2 dose (RP2D). Toxicities were graded per CTCAE v5.0. An expansion cohort additionally incorporated a seven-day run-in of telaglenastat monotherapy at RP2D prior to radiation to evaluate the pharmacodynamic impact of telaglenastat on plasma and tumor metabolites. 23 patients with IDH mutant astrocytoma (WHO grade 2, n = 5; WHO grade 3, n = 18) were accrued between December 2018 and January 2022 (Dose Escalation: 16; Dose Expansion: 7). Median age was 32 years (range 23-69 years). 61% were male and 70% were ECOG 0. No dose-limiting toxicities were observed. Grade 3/4 adverse events (independent of attribution) included: lymphopenia (3), neutropenia (2), leukocytosis (2), alanine transaminase elevation (2), thrombocytopenia (1), leukopenia (1), maculopapular rash (1), hyperglycemia (1), hyponatremia (1). The RP2D of concurrent telaglenastat was defined as 800 mg twice daily. Following peak absorption on Day 15 at RP2D, the mean (%CV) terminal elimination half-life in the plasma was 4.2 (53.5%) hours (range 2.1-7.1 hours). The Cmax, Tmax, oral clearance, and AUC were 1496 ng/mL, 4.0 hr, 93.6 L/hr/m2, and 7430 ng/mL*hr, respectively.

Inhibition of 11β-Hydroxysteroid dehydrogenase-1 with AZD4017 in patients with nonalcoholic steatohepatitis or nonalcoholic fatty liver disease: A randomized, double-blind, placebo-controlled, phase II study

AIM

To evaluate whether short-term treatment with a selective 11β-Hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibitor, AZD4017, would block hepatic cortisol production and thereby decrease hepatic fat in patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), with or without type 2 diabetes (T2D).

MATERIALS AND METHODS

This was a randomized, double-blind, placebo-controlled, phase 2 study conducted at two sites. Key inclusion criteria were the presence of NAFLD or NASH on magnetic resonance imaging (MRI) or recent biopsy positive for NASH. Enrolled patients were randomly assigned (1:1) to AZD4017 or placebo for 12 weeks. Primary outcomes were between-group differences in mean change from baseline to week 12 in liver fat fraction (LFF) and conversion of ¹³ C cortisone to ¹³ C cortisol in the liver.

RESULTS

A total of 93 patients were randomized; 85 patients completed treatment. The mean (standard deviation [SD]) change in LFF was -0.667 (5.246) and 0.139 (4.323) in the AZD4017 and placebo groups (P = 0.441). For patients with NASH and T2D, the mean (SD) change in LFF was significantly improved in the AZD4017 versus the placebo group (-1.087 [5.374] vs. 1.675 [3.318]; P = 0.033). Conversion of ¹³ C cortisone to ¹³ C cortisol was blocked in all patients in the AZD4017 group. There were no significant between-group differences (AZD4017 vs. placebo) in changes in fibrosis, weight, levels of liver enzymes or lipids, or insulin sensitivity.

CONCLUSION

Although the study did not meet one of the primary outcomes, AZD4017 blocked the conversion of ¹³ C cortisone to ¹³ C cortisol in the liver in all patients who received the drug. In patients with NASH and T2D, AZD4017 improved liver steatosis versus placebo.

Efficacy and Safety of Endoscopic Balloon Placement for Weight Loss in Patients With Cirrhosis Awaiting Liver Transplantation

The efficacy and safety of a fluid-filled intragastric balloon (IGB) for weight loss in patients with cirrhosis on the liver transplantation (LT) waiting list is unknown. We enrolled stable compensated patients with body mass index >35 kg/m² and on the waiting list for IGB placement endoscopically for a maximum of 6 months. A total of 8 patients (7 men) aged mean ± SD, 56 ± 4.6 years with Model for End-Stage Liver Disease-sodium (MELD-Na) scores 14.1 ± 3.4 experienced weight reduction (146 ± 22.2 kg versus 127 ± 21.6 kg [P = 0.005] with IGB in place and 130 ± 24.6 kg [P = 0.014] at 6 months), with a total body weight loss of 12.2% ± 8.8% with IGBs in place and 10.9% ± 8.9% at 6 months. Body fat decreased from 48.6% ± 5.8% to 40.6% ± 6.4% (P = 0.001) and lean mass increased from 51.3% ± 6% to 59.4% ± 6.4% (P = 0.001). No change in MELD-Na scores occurred (P = 0.770). Early balloon retrieval was attributed to accommodative symptoms (n = 2) and liver decompensation (n = 1). Mallory Weiss tears (n = 3), but no portal hypertensive bleeding, occurred. Liver decompensation and/or hepatocellular carcinoma (HCC) developed in 3 patients. A total of 4 patients with LT ± sleeve gastrectomy maintained overall weight loss. Of 4 patients who did not receive transplants, 2 experienced weight regain. IGB results in short-term weight loss in patients with cirrhosis awaiting LT, with body fat loss without lean mass loss. Adverse effects were common. Decompensation and HCC did occur, with uncertainty of the relation to weight loss, and thus careful patient selection and close follow-up are required.

Optic Nerve Choristoma Mimicking a Neurenteric Cyst

Optic nerve choristomas are rare entities in which a developmental focus of histologically normal tissue is abnormally located within or along a segment of the optic nerve. Although benign, choristomas may demonstrate slow growth, ultimately resulting in visual field deficits due to compression of the adjacent nerve in the few cases reported in the anterior fossa. Choristomas may have cystic components, though this has not been described in such lesions along the optic nerve. Here, a predominantly cystic optic nerve choristoma is described, with radiologic features mimicking those of an anterior cranial fossa neurenteric cyst. The case highlights the radiology-pathology correlates of choristomas and reviews the surgical approach and management of patients with such lesions.

A phase Ib trial of CB-839 (telaglenastat) in combination with radiation therapy and temozolomide in patients with IDH-mutated diffuse astrocytoma and anaplastic astrocytoma (NCT03528642)

TPS2075

Background: IDH mutant astrocytomas express high levels of 2-hydroxyglutarate (2-HG), an oncogenic metabolite which drives gliomagenesis. Excess 2-HG inhibits branched chain amino acid transaminase, which catalyzes glutamate synthesis from branched chain amino acids. This defect causes these tumors to become more reliant on glutaminase for glutamate biosynthesis from glutamine. CB-839 (telaglenastat) is a novel glutaminase inhibitor which is well tolerated in humans. McBrayer et al have recently demonstrated that CB-839 further depletes intracellular glutamate and glutathione in IDH mutant glioma cells, and enhances RT (radiation therapy) efficacy in an orthotopic glioma model. Methods: NCI #10218 is a CTEP supported phase I clinical trial investigating the safety and tolerability of CB-839 when combined with RT/TMZ (temozolomide) in patients with previously untreated IDH mutant grade II/III astrocytoma. Patients with grade II and III astrocytomas will be treated with 50.4 and 59.4 Gy of RT, respectively, with standard doses of concurrent TMZ. CB-839 will also be administered orally concurrently with RT, with doses escalated in cohorts based on a standard 3+3 design. After defining the maximum tolerated dose (MTD) of CB-839, an expansion cohort will evaluate the pre- and post-CB-839 therapy metabolome of patients with IDH mutant astrocytoma. Enrollment to this cohort will require measurable disease and patients will additionally be treated with a 7 day run-in of CB-839 at MTD prior to RT. The effect of CB-839 on the metabolome will be studied in both plasma (LC/MS/MS) and tumor (magnetic resonance spectroscopy), along with PK to confirm adequacy of systemic exposure. Preliminary data on neurocognitive endpoints will also be acquired. NCI #10218 is currently activated for enrollment to cohort 1. Clinical trial information: NCT03528642.

A Deep Learning-Based Approach to Reduce Rescan and Recall Rates in Clinical MRI Examinations

BACKGROUND AND PURPOSE

MR imaging rescans and recalls can create large hospital revenue loss. The purpose of this study was to develop a fast, automated method for assessing rescan need in motion-corrupted brain series.

MATERIALS AND METHODS

A deep learning-based approach was developed, outputting a probability for a series to be clinically useful. Comparison of this per-series probability with a threshold, which can depend on scan indication and reading radiologist, determines whether a series needs to be rescanned. The deep learning classification performance was compared with that of 4 technologists and 5 radiologists in 49 test series with low and moderate motion artifacts. These series were assumed to be scanned for 2 scan indications: screening for multiple sclerosis and stroke.

RESULTS

The image-quality rating was found to be scan indication- and reading radiologist-dependent. Of the 49 test datasets, technologists created a mean ratio of rescans/recalls of (4.7 ± 5.1)/(9.5 ± 6.8) for MS and (8.6 ± 7.7)/(1.6 ± 1.9) for stroke. With thresholds adapted for scan indication and reading radiologist, deep learning created a rescan/recall ratio of (7.3 ± 2.2)/(3.2 ± 2.5) for MS, and (3.6 ± 1.5)/(2.8 ± 1.6) for stroke. Due to the large variability in the technologists' assessments, it was only the decrease in the recall rate for MS, for which the deep learning algorithm was trained, that was statistically significant (P = .03).

CONCLUSIONS

Fast, automated deep learning-based image-quality rating can decrease rescan and recall rates, while rendering them technologist-independent. It was estimated that decreasing rescans and recalls from the technologists' values to the values of deep learning could save hospitals $24,000/scanner/year.

Increased Curvature of the Tentorium Cerebelli in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

Transverse sinus effacement is detectable on MRV examinations in almost all patients with idiopathic intracranial hypertension. This effacement of the transverse sinus is presumed to be mediated by elevation of intracranial pressure, resulting in compression and inward collapse of the dural margins of the sinus. We sought to establish whether supratentorial broad-based downward deformity of the tentorium might explain transverse sinus effacement in idiopathic intracranial hypertension.

MATERIALS AND METHODS

MRV examinations of 53 adult patients with idiopathic intracranial hypertension were reviewed retrospectively and compared with 58 contemporaneously acquired controls. The curvature of the tentorium with reference to a line connecting the transverse sinus laterally with the confluence of the tentorial leaves medially was calculated as a segment of a circle. The height and area of the segment and the angle subtended by the midpoint of the tentorium from the falx were calculated.

RESULTS

The height and area of the segment described by the chord connecting the transverse sinus with the apex of the tentorial confluence and subtended midtentorial angle were greater in the idiopathic intracranial hypertension group; this finding supports the hypothesis that increased tentorial bowing is present in idiopathic intracranial hypertension.

CONCLUSIONS

Increased bowing of the tentorium in patients with idiopathic intracranial hypertension compared with controls is a new observation, lending itself to new hypotheses on the nature and localization of elevated intracranial pressure in idiopathic intracranial hypertension. Bowing of the tentorium may play a part in distorting the contour of the transverse sinuses, resulting, at least in part, in the effacement of the transverse sinuses in idiopathic intracranial hypertension.

Randomized Controlled Trial of a MUFA or Fiber-Rich Diet on Hepatic Fat in Prediabetes

CONTEXT

Increased prevalence of type 2 diabetes mellitus and prediabetes worldwide is attributed in part to an unhealthy diet.

OBJECTIVE

To evaluate whether 12 weeks of high monounsaturated fatty acid (MUFA) or fiber-rich weight-maintenance diet lowers hepatic fat and improves glucose tolerance in people with prediabetes.

DESIGN

Subjects underwent a [6, 6-2H2]-labeled 75-g oral glucose tolerance test to estimate hepatic insulin sensitivity and liver fat fraction (LFF) using magnetic resonance spectroscopy before and after intervention.

SETTING

Mayo Clinic Clinical Research Trials Unit.

PARTICIPANTS

43 subjects with prediabetes.

INTERVENTION

Subjects were randomized into three isocaloric weight-maintaining diets containing MUFA (olive oil), extra fiber, and standard US food (control-habitual diet).

OUTCOME MEASURES

LFF, glucose tolerance, and indices of insulin action and secretion.

RESULTS

Body weight was maintained constant in all groups during the intervention. Glucose and hormonal concentrations were similar in all groups before, and unchanged after, 12 weeks of intervention. LFF was significantly lower after intervention in the MUFA group (P < 0.0003) but remained unchanged in the fiber (P = 0.25) and control groups (P = 0.45). After 12 weeks, LFF was significantly lower in the MUFA than in the control group (P = 0.01), but fiber and control groups did not differ (P = 0.41). Indices of insulin action and secretion were not significantly different between the MUFA and control groups after intervention (P ≥ 0.11), but within-group comparison showed higher hepatic (P = 0.01) and total insulin sensitivity (P < 0.04) with MUFA.

CONCLUSIONS

Twelve weeks of a MUFA diet decreases hepatic fat and improves both hepatic and total insulin sensitivity.

Spinal subdural hematoma: a rare case of spinal subdural hematoma complicating routine, minimally invasive lumbar discectomy and decompression and relevant literature review

We present a case of apparently uncomplicated lumbar decompression and discectomy with delayed postoperative neurological deterioration secondary to subdural hematoma at the thoracolumbar level of the spinal cord. Previously described subdural hematomas have occurred spontaneously or related to iatrogenic injury. Hitherto, no case of acute postoperative subdural hematoma has been reported in the postoperative setting in the absence of known iatrogenic dural injury. A 76-year-old male with central and lateral recess spinal stenosis underwent apparently uncomplicated bilateral L3-4 and left sided L4-5 decompressive partial laminectomies and discectomy. No incidental dural injury or cerebrospinal fluid leak was detected. On postoperative day two, he developed progressive, profound weakness, sensory changes and urinary retention. Magnetic resonance imaging (MRI) demonstrated a compressive subdural fluid collection extending between T11-L2, which was confirmed to be xanthochromic and under pressure superficial to an undisturbed arachnoid at emergent surgical exploration and evacuation. The mechanism of this complication is unknown. The patient went on to a complete recovery following surgical evacuation of the fluid via durotomy. While this is a very rare event, it reminds that a high index of suspicion is required with a low threshold for urgent imaging and intervention in the postoperative period upon development of unexpected, progressive and/or profound neurological findings regardless of intraoperative course.

Transverse Sinus Stenosis Is the Most Sensitive MR Imaging Correlate of Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

Patients with idiopathic intracranial hypertension have transverse sinus stenosis on gadolinium-bolused MRV, but other MR imaging signs are less consistently seen. Our aim was to demonstrate that transverse sinus stenosis could be identified on conventional MR imaging, and this identification would allow improved diagnostic sensitivity to this condition.

MATERIALS AND METHODS

MR imaging and MRV images from 63 patients with idiopathic intracranial hypertension and 96 controls were reviewed by using 3 independent procedures. MRV images were graded for the presence and degree of stenosis of the transverse sinus. Postgadolinium coronal T1-weighted sequences were evaluated independent of MRV. The dimensions of the proximal and distal transverse sinus were measured from the MRV examinations, and the cross-sectional area of the transverse sinus was calculated. Correlation among the 3 modes of evaluation of the transverse sinus was conducted by using Wilcoxon/Kruskal-Wallis, Pearson, and Spearman ρ nonparametric statistical techniques.

RESULTS

Transverse sinus stenosis was identified bilaterally on MRV in 94% of patients with idiopathic intracranial hypertension and in 3% of controls. On coronal T1 postgadolinium MR images, transverse sinus stenosis was identified in 83% of patients with idiopathic intracranial hypertension and 7% of controls. Previously described MR imaging signs of intracranial hypertension were identified in 8%-61% of patients with idiopathic intracranial hypertension. Correlation among the 3 modes of evaluation was highly significant (P < .0001).

CONCLUSIONS

Even without the assistance of an MRV sequence, neuroradiologists can validly identify bilateral transverse sinus stenosis in patients with intracranial hypertension more reliably than other previously described MR imaging findings in this condition. We conclude that transverse sinus stenosis is the most useful and sensitive imaging indicator of this disease state.

The case of the missing glutamine

A theoretical study was performed to determine the accuracy and repeatability of multiple one-dimensional pulse sequences in the quantification of glutamine concentration at 3 T. Variable repeatability (12% to > 50%) and significant absolute error (-50% to +70%) were noted for the eight pulse sequences considered. Data acquired in vivo using three of the pulse sequences used for simulation matched the predicted repeatability well; among the pulse sequences considered, point-resolved spectroscopy (TE = 80 ms) offered minimal error and acceptable repeatability (12%) for brain glutamine measurements. Following correction for the expected bias of each pulse sequence, consistent glutamine measurements, in the 1-mM range, were reported with the three sequences. An explanation for the mismatch between in vivo (1)H MRS and in vitro (13)C/(1)H MRS at high field was attempted.

Ganglioglioma of the right optic tract: Case report and review of the literature

We describe a case of ganglioglioma of the right optic tract in a 52-year-old woman. Review of the general literature discloses only 11 cases of tumors of the visual pathway that meet the histological criteria for such neoplasm. A detailed radiological description of our case and a review of the literature is provided.

Different generators in human temporal-parasylvian cortex account for subdural laser-evoked potentials, auditory-evoked potentials, and event-related potentials

In order to localize cortical areas mediating pain we now report subdural cortical potentials evoked by auditory stimulation (auditory-evoked potentials - AEPs) and by cutaneous stimulation with a laser (laser-evoked potentials - LEPs). Stimulation with the laser evokes a pure pain sensation by selective activation of nociceptors. LEPs were maximal over the inferior aspect of the central sulcus and had the same polarity on either side of the sylvian fissure. AEPs were maximal posterior to the LEP maximum and had opposite polarity on opposite sides of the sylvian fissure, consistent with the location of a known generator in the temporal operculum. Auditory P3 (event-related) potentials were maximal over the temporal base. These findings demonstrate that the LEP generator is not in secondary somatosensory cortex on the parietal operculum and is different from the P3 generator.

Lymphoepithelial cyst (LEC) of the pancreas: cytomorphology and differential diagnosis on fine-needle aspiration (FNA)

Lymphoepithelial cyst (LEC) of the pancreas is an extremely rare benign entity. We describe the cytopathologic findings of such a lesion in a 49-yr-old woman who was examined for epigastric pain. A trans-esophageal ultrasound-guided fine-needle aspiration of a pancreatic mass disclosed an intimate mixture of squamous epithelial cells and small, mature lymphocytes in a background of keratinaceous debris, anucleate squames, and multinucleated histiocytes. On histopathologic examination, a subsequent resection showed a multiloculated cystic lesion with a stratified squamous epithelial lining surrounded by well-formed lymphoid tissue, suggestive of LEC. The differential diagnosis includes other pancreatic pseudocysts, dermoid cyst, mucinous cystic neoplasms, adenosquamous carcinoma, and metastatic squamous cell carcinoma.

Intraabdominal desmoplastic small round cell tumor: cytopathologic findings in two cases

Intraabdominal desmoplastic small round cell tumor (DSRCT) is an extremely rare entity. This study describes fine-needle aspiration, ascitic fluid, and touch imprint cytomorphology of DSRCT in 2 patients with extensive abdomino-pelvic disease. Cytopathologic features were unique and showed good morphologic correlation with subsequent histology of the resected tumor. Immunocytochemical profile and differential diagnosis with other small round cell tumors in this age group are also discussed.

Meniscal repair supplemented with exogenous fibrin clot and autogenous cultured marrow cells in the goat model

This study was undertaken to evaluate the placement of fibrin clot and cultured autologous marrow cells in surgically created, full-thickness, meniscal lesions in the avascular zone in 32 female Spanish goats. The menisci were repaired with two vertically oriented sutures (N = 8), exogenous fibrin clot was placed into the meniscal defect before placement of the two sutures (N = 8), fibrin clot plus cultured adherent bone marrow cells were placed in the defect (N = 8), or the meniscal lesions were left unrepaired (N = 8). On gross and manual inspection, meniscal lesions showed some degree of healing in all animals except for the eight unrepaired lesions. All the experimental specimens had decreased tensile strength compared with the contralateral control medial menisci. Ultimate load to failure, energy absorbed to failure, and stiffness were less than 40% of the controls for all groups. Histologic sections demonstrated focal cellular areas consisting of giant cells and macrophages in the repair sites. Our observations failed to demonstrate a statistically significant enhancement of healing with the use of exogenous fibrin clot compared with vertically oriented sutures alone. The addition of cultured adherent autologous bone marrow-derived cells in conjunction with the fibrin clot did not enhance the meniscal healing.

Regulation of the mRNA-binding protein AUF1 by activation of the beta-adrenergic receptor signal transduction pathway

In both cell culture based model systems and in the failing human heart, beta-adrenergic receptors ( beta-AR) undergo agonist-mediated down-regulation. This decrease correlates closely with down-regulation of its mRNA, an effect regulated in part by changes in mRNA stability. Regulation of mRNA stability has been associated with mRNA-binding proteins that recognize A + U-rich elements within the 3'-untranslated regions of many mRNAs encoding proto-oncogene and cytokine mRNAs. We demonstrate here that the mRNA-binding protein, AUF1, is present in both human heart and in hamster DDT1-MF2 smooth muscle cells and that its abundance is regulated by beta-AR agonist stimulation. In human heart, AUF1 mRNA and protein was significantly increased in individuals with myocardial failure, a condition associated with increases in the beta-adrenergic receptor agonist norepinephrine. In the same hearts, there was a significant decrease (approximately 50%) in the abundance of beta1-AR mRNA and protein. In DDT1-MF2 cells, where agonist-mediated destabilization of beta2-AR mRNA was first described, exposure to beta-AR agonist resulted in a significant increase in AUF1 mRNA and protein (approximately 100%). Conversely, agonist exposure significantly decreased (approximately 40%) beta2-adrenergic receptor mRNA abundance. Last, we demonstrate that AUF1 can be immunoprecipitated from polysome-derived proteins following UV cross-linking to the 3'-untranslated region of the human beta1-AR mRNA and that purified, recombinant p37AUF1 protein also binds to beta1-AR 3'-untranslated region mRNA.

Juxta-articular synovial cyst of the shoulder

A case of an unusual synovial cyst with both intra- and extraosseous components found in the proximal humerus of a patient with osteoarthritis is presented. The importance of this lesion is that it should be recognized as a manifestation of the underlying osteoarthritis and does not represent a more serious primary lesion.

Hypoglycemia with glycerol salvage: a role in anti-neoplastic therapy?

Most tumors are obligate glucose consumers and severe glucose depletion has anti-neoplastic effects. However, an alternate energy source is necessary to support the host. Since glycerol is utilized by all hypoglycemic sensitive normal tissues but not tumors, glycerol may be an ideal alternate energy source. The effects of glycerol on tumor growth, animal survival during systemic hypoglycemia induced by 3-mercaptopicolinic acid (3-MP, a gluconeogenesis inhibitor), and effects of 3-MP on gluconeogenesis from glycerol were studied. Experiment 1-glycerol effect on tumor cell growth; and glycerokinase activity assay. Methylcholanthrene-induced (MCA) sarcoma cells were plated in either glucose free, glucose or glycerol containing medium. Cell counts and viabilities were recorded daily. Cells in glucose group had normal growth pattern and cell viability, while cell counts and viabilities in control and glycerol groups decreased markedly. F344 rats were injected with MCA-sarcoma cells in the flank. Glycerokinase activities in tumor and host liver were assayed on day 20. Activities were 12.3 +/- 2.8, 148.2 + 17.5 assayed on day 20. Activities were 12.3 +/- 2.8, 148.2 +/- 17.5 mumol/g protein/min in tumor and liver, respectively. Experiment 2-glycerol effect on animal survival during hypoglycemia induced by 3-MP. Following a 48 hour fast, 12 Fischer 344 rats were injected (ip) with 3-MP (200mg/kg) and randomized to saline or glycerol perfusion (100mg/kg/hr) groups. Four of 6 rats in the saline group died of hypoglycemia. All rats in the glycerol group survived, but blood glucose levels were increased as compared to the saline group. Experiment 3-3-MP effect on gluconeogenesis from glycerol as compared to lactate. 5 x 10(6) hepatocytes were incubated in glucose-free HBSS containing glycerol (20mM) or lactate (20mM) in the presence (0.5mM) or absence of 3-MP. Glucose production was assayed every 30 minutes for 2 hrs. Glucose production from glycerol was not significantly inhibited in the presence of 3-MP as compared to lactate.

CONCLUSION

Glycerol does not support MCA-sarcoma growth and promotes animal survival during severe systemic hypoglycemia induced by 3-MP. However, glycerol also led to increased gluconeogenesis in this model. The use of hypoglycemic agents with glycerol protection of host tissues warrants further study.

Preparation of an exogenous fibrin clot

Exogenous fibrin clot has been proposed to promote the healing of meniscal tears in areas of compromised vascularity. We present a method to reproducibly prepare a tightly wound exogenous fibrin clot using 5 to 10 mL of blood obtained by sterile venipuncture. The technique produces a clot of increased consistency and high fibrin content that is adaptable in preparation as a longer, thinner clot or a shorter, thicker clot. Clots prepared in this manner will hold suture or can be morselized for extrusion through a syringe.

A theory of cooperativity modulation in neural networks as an important parameter of CNS catecholamine function and induction of psychopathology

Recent research in computational neuroscience has suggested that psychosis associated with disturbed catecholamine neurotransmission may result from disturbances in the gain parameters of neural networks that these same secondary neurotransmitters are thought to control. We propose a mathematical model based upon cooperativity theory used in thermodynamics to explain how the gain parameter that momentarily increases the effect upon the post-synaptic cell of a given weighted connection from the presynaptic cell could be instantiated in the fluctuating electrical conductance of the dendrite of a neuron without requiring extensive ion transport or utilization of the ATP energy cycle. More specifically we propose that catecholamine neurotransmission serves to maintain the dendrite in a cooperative state with regard to changes in electrical conductance due to impulse traffic alone. In this way we supply the neuron with an activity driven gain parameter that not only increases volume of neuronal output at very low energy cost but that also upscales cooperative effects at the mechanico-chemical level of the dendrite to the network level itself. An important implication of this model is that two extreme states for dendritic electrical conductance will occur if cooperativity is lost at the level of catecholamine depletion or excess due to drug effects. These are the AND gate effect in which dendritic conductance is so low that the neuron requires extensive synaptic activity in order to output significantly. We correlate this state with negative symptoms in schizophrenia and psychomotor retardation in depression as well as the rigidity in Parkinsonism. The other extreme is represented by the OR gated dendrite in which conductance is so high that even noisy input to the dendrite will lead to significant nerve cell output. We correlate this condition with the positive symptoms of schizophrenia, the agitated features of psychotic depression and the tremors of Parkinsonism.