Michael M. Haglund

DNA mismatch repair and O6-alkylguanine-DNA alkyltransferase analysis and response to Temodal in newly diagnosed malignant glioma

PURPOSE We evaluated the response to Temodal (Schering-Plough Research Institute, Kenilworth, NJ) of patients with newly diagnosed malignant glioma, as well as the predictive value of quantifying tumor DNA mismatch repair activity and O6-alkylguanine-DNA alkyltransferase (AGT). PATIENTS AND METHODS Thirty-three patients with newly diagnosed glioblastoma multiforme (GBM) and five patients with newly diagnosed anaplastic astrocytoma (AA) were treated with Temodal at a starting dose of 200 mg/m2 daily for 5 consecutive days with repeat dosing every 28 days after the first daily dose. Immunochemistry for the detection of the human DNA mismatch repair proteins MSH2 and MLH1 and the DNA repair protein AGT was performed with monoclonal antibodies and characterized with respect to percent positive staining. RESULTS Of the 33 patients with GBM, complete responses (CRs) occurred in three patients, partial responses (PRs) occurred in 14 patients, stable disease (SD) was seen in four patients, and 12 patients developed progressive disease (PD). Toxicity included infrequent grades 3 and 4 myelosuppression, constipation, nausea, and headache. Thirty tumors showed greater than 60% cells that stained for MSH2 and MLH1, with three CRs, 12 PRs, three SDs, and 12 PDs. Eight tumors showed 60% or less cells that stained with antibodies to MSH2 and/or MLH1, with 3 PRs, 3 SDs, and 2 PDs. Eleven tumors showed 20% or greater cells that stained with an antibody to AGT, with 1 PR, 2 SDs, and 8 PDs. Twenty-five tumors showed less than 20% cells that stained for AGT, with 3 CRs, 12 PRs, 4 SDs, and 6 PDs. CONCLUSION These results suggest that Temodal has activity against newly diagnosed GBM and AA and warrants continued evaluation of this agent. Furthermore, pretherapy analysis of tumor DNA mismatch repair and, particularly, AGT protein expression may identify patients in whom tumors are resistant to Temodal.

Cortical localization of temporal lobe language sites in patients with gliomas.

In a series of 40 patients undergoing an awake craniotomy for the removal of a glioma of the dominant hemisphere temporal lobe, cortical stimulation mapping was used to localize essential language sites. These sites were localized to distinct temporal lobe sectors and compared with 83 patients without tumors who had undergone language mapping for the treatment of intractable epilepsy. In patients with and without temporal lobe gliomas, the superior temporal gyrus contained significantly more language sites than the middle temporal gyrus. Both patient populations also had language sites anterior to the central sulcus in the superior temporal gyrus (12-16%). The patients without tumors had significantly more language sites in the superior temporal gyrus, compared with the superior temporal gyrus of patients with temporal lobe tumors. Multiple variables were studied for their effect on preoperative and postoperative language deficits and included age, sex, number of language sites, histology, size of the tumor, and the distance of tumor resection margins from the nearest language site. The distance of the resection margin from the nearest language site was the most important variable in determining the improvement in preoperative language deficits, the duration of postoperative language deficits, and whether the postoperative language deficits were permanent. If the distance of the resection margin from the nearest language site was > 1 cm, significantly fewer permanent language deficits occurred. Cortical stimulation mapping for the identification of essential language sites in patients with gliomas of the dominant hemisphere temporal lobe will maximize the extent of tumor resection and minimize permanent language deficits.

Irinotecan Therapy in Adults With Recurrent or Progressive Malignant Glioma

PURPOSE To determine the activity, toxicity, and pharmacokinetics of irinotecan (CPT-11, Camptosar; Pharmacia & Upjohn, Kalamazoo, MI) in the treatment of adults with progressive, persistent, or recurrent malignant glioma. PATIENTS AND METHODS Patients with progressive or recurrent malignant gliomas were enrolled onto this study between October 1996 and August 1997. CPT-11 was given as a 90-minute intravenous (i.v.) infusion at a dose of 125 mg/m2 once weekly for 4 weeks followed by a 2-week rest, which comprised one course. Plasma concentrations of CPT-11 and its metabolites, SN-38 and SN-38 glucuronide (SN-38G), were determined in a subset of patients. RESULTS All 60 patients who enrolled (36 males and 24 females) were treated with CPT-11 and all were assessable for toxicity, response, and survival. Pharmacokinetic data were available in 32 patients. Nine patients (15%; 95% confidence interval, 6% to 24%) had a confirmed partial response, and 33 patients (55%) achieved stable disease lasting more than two courses (12 weeks). Toxicity observed during the study was limited to infrequent neutropenia, nausea, vomiting, and diarrhea. CPT-11, SN-38, and SN-38G area under the plasma concentration-time curves through infinite time values in these patients were approximately 40%, 25%, and 25%, respectively, of those determined previously in patients with metastatic colorectal cancer not receiving antiepileptics or chronic dexamethasone treatment. CONCLUSION Response results document that CPT-11, given with a standard starting dose and treatment schedule, has activity in patients with recurrent malignant glioma. However, the low incidence of severe toxicity and low plasma concentrations of CPT-11 and SN-38 achieved in this patient population suggest that concurrent treatment with anticonvulsants and dexamethasone enhances drug clearance.

Phase I trial of O6-benzylguanine for patients undergoing surgery for malignant glioma.

PURPOSE The major mechanism of resistance to alkylnitrosourea therapy is the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT), which removes chlorethylation or methylation damage from the O6-position of guanine. O6-benzylguanine (O6-BG) is an AGT substrate that inhibits AGT by suicide inactivation. We conducted a phase I trial to define the presurgical dose required for depletion of tumor AGT activity in patients with malignant glioma. MATERIALS AND METHODS Patients were to be treated 18 hours before craniotomy with intravenous doses that ranged between 40 and 100 mg/m2 given over 1 hour. Resected tumor was snap-frozen in liquid nitrogen and AGT activity analyzed by high-pressure liquid chromatography (HPLC). Up to 13 patients were treated at a specific dose of O6-BG, with a target end point of > or = 11 of 13 patients with undetectable tumor AGT levels (< 10 fmol/mg protein). RESULTS Thirty patients with malignant gliomas were enrolled, with 11 of 11 patients treated at 100 mg/m2 O6-BG demonstrating tumor AGT levels less than 10 fmol/mg protein. No toxicity was noted in any patient treated. CONCLUSION These results indicate that 100 mg/m2 of O6-BG can maintain tumor AGT levels less than 10 fmol/mg protein for at least 18 hours after treatment, a time interval in which bis(2-chloroethyl)nitrosourea (BCNU)-induced chloroethyl adducts are fully converted into interstrand cross-links. A 100-mg/m2 dose of O6-BG will be used in combination with BCNU in another phase I trial designed to determine the maximal-tolerated dose of BCNU.

Enhanced optical imaging of rat gliomas and tumor margins.

Current intraoperative methods used to maximize the extent of tumor removal are limited to intraoperative biopsies, ultrasound, and stereotactic volumetric resections. A new technique involving the optical imaging of an intravenously injected dye has the potential to localize tumors and their margins with a high degree of accuracy. In a rat glioma model, enhanced optical imaging was performed and indocyanine green was used as the contrast-enhancing agent. In all 22 animals, the peak optical change in the tumor was greater than in the ipsilateral brain around the tumor and the contralateral normal hemisphere. The clearance of the dye was significantly delayed to a greater extent in the tumor than in the brain around the tumor and the normal brain. After attempts were made at complete microscopic resection, enhanced optical imaging of the tumor margins and the histological samples demonstrated a specificity of 93% and a sensitivity of 89.5%. Enhanced optical imaging was capable of outlining the tumor even when the imaging was done through the cranium. The optical imaging of rat gliomas with a contrast-enhancing dye is able to differentiate between normal brain and tumor tissue both at the cortical surface and at the tumor margins. The application of these studies in an intraoperative clinical setting may allow for the more accurate determination of tumor margins and may increase the extent of tumor removal.

Phase II Trial of Carmustine Plus O6-Benzylguanine for Patients With Nitrosourea-Resistant Recurrent or Progressive Malignant Glioma

PURPOSE We conducted a phase II trial of carmustine (BCNU) plus the O(6)-alkylguanine-DNA alkyltransferase inhibitor O(6)-benzylguanine (O(6)-BG) to define the activity and toxicity of this regimen in the treatment of adults with progressive or recurrent malignant glioma resistant to nitrosoureas. PATIENTS AND METHODS Patients were treated with O(6)-BG at an intravenous dose of 120 mg/m(2) followed 1 hour later by 40 mg/m(2) of BCNU, with cycles repeated at 6-week intervals. RESULTS Eighteen patients were treated (15 with glioblastoma multiforme, two with anaplastic astrocytoma, and one with malignant glioma). None of the 18 patients demonstrated a partial or complete response. Two patients exhibited stable disease for 12 weeks before their tumors progressed. Three patients demonstrated stable disease for 6, 12, and 18 weeks before discontinuing therapy because of hematopoietic toxicity. Twelve patients experienced reversible > or = grade 3 hematopoietic toxicity. There was no difference in half-lives (0.56 +/- 0.21 hour v 0.54 +/- 0.20 hour) or area under the curve values (4.8 +/- 1.7 microg/mL/h v 5.0 +/- 1.3 microg/mL/h) of O(6)-BG for patients receiving phenytoin and those not treated with this drug. CONCLUSION These results indicate that O(6)-BG plus BCNU at the dose schedule used in this trial is unsuccessful in producing tumor regression in patients with nitrosourea-resistant malignant glioma, although stable disease was seen in five patients for 6, 12, 12, 12, and 18 weeks. Future use of this approach will require strategies to minimize dose-limiting toxicity of BCNU such as regional delivery or hematopoietic stem-cell protection.

Spontaneous Rhythmic Synchronous Activity in Epileptic Human and Normal Monkey Temporal Lobe

Summary: Intracellular recordings were obtained from neurons in tissue taken from human epileptic temporal lobe and normal monkey hippocampus. Using the in vitro slice preparation, we confirmed that spontaneous rhythmic synchronous events (SRSEs) were predominantly found in cells of mesial temporal lobe. These synaptic‐like events appeared to be mediated by a GABAergic mechanism, since they were blocked by bicuculline. An interneuron‐like cell type was found which discharged in a burst pattern in parallel with SRSE occurrence in pyramidal neurons. Burst discharges were graded and excitatory postsynaptic potential (EPSP)‐triggered; all‐or‐none paroxysmal depolarizations were extremely rare. These features of SRSE activity suggest that population synchrony in this tissue is largely dependent on local inhibitory interneuronal circuitry. SRSEs were found in normal monkey hippocampus as well as in mesial tissue from human epileptic temporal lobe. This result indicates that SRSEs are not a direct reflection of tissue epileptogenicity. However, the circuitry underlying SRSEs may be important in the determination of tissue seizure susceptibility, since it provides a substrate for cell synchronization.

Possible Role for Vascular Cell Proliferation in Cerebral Vasospasm After Subarachnoid Hemorrhage

Background and Purpose— During vasospasm after subarachnoid hemorrhage (SAH), cerebral blood vessels show structural changes consistent with the actions of vascular mitogens. We measured platelet-derived vascular growth factors (PDGFs) in the cerebrospinal fluid (CSF) of patients after SAH and tested the effect of these factors on cerebral arteries in vivo and in vitro. Methods— CSF was sampled from 14 patients after SAH, 6 patients not suffering SAH, and 8 normal controls. ELISA was performed for PDGF-AB, transforming growth factor-&bgr;1, and vascular endothelial growth factor. A mouse model was used to compare cerebral vascular cell proliferation and PDGF staining in SAH compared with sham-operated controls. Normal human pial arteries were incubated for 7 days in vitro, 2 groups with human blood clot and 1 with and 1 without PDGF antibodies. Results— PDGF-AB concentrations in CSF from SAH patients were significantly higher than those from non-SAH patients and normal controls, both during the first week after SAH and for all time points measured. Smooth muscle and fibroblast proliferation was observed after SAH in the mouse model, and this cellular replication was observed in conjunction with PDGF protein at the sites of thrombus. In human pial arteries, localized thrombus stimulated vessel wall proliferation, and proliferation was blocked by neutralizing antibodies directed against PDGFs. Conclusions— Vascular mitogens are increased in the CSF of patients after SAH. Proliferation of cells in the vascular wall is associated with perivascular thrombus. Cellular proliferation and subsequent vessel wall thickening may contribute to the syndrome of delayed cerebral vasospasm.

Intraventricular hemorrhage in blunt head trauma: an analysis of 43 cases.

Before the advent of computed tomography, intraventricular hemorrhage (IVH) from any source was thought rare and invariably fatal. Although intraventricular blood is readily identifiable with computed tomography, there has been little systematic study of its significance in blunt head trauma. Forty-three patients with traumatic IVH were prospectively identified in 1 year at Harborview Medical Center (University of Washington). Most were victims of motor vehicle accidents and suffered severe head injuries. IVH occurred alone in two patients; superficial contusions and subarachnoid hemorrhage were the most common associated finding. Blood was present in only one or both lateral ventricles in 25 patients; only the 3rd or 4th ventricles in 4 and all ventricles in 14 instances. There were 3 intracerebral hematomas and 14 basal ganglion hemorrhages. All of the former and half of the latter communicated with the adjacent lateral ventricle. Extra-axial hematomas appeared more common when only the lateral ventricles were involved, whereas corpus callosum or brain-stem hemorrhage appeared more likely when all the ventricles were involved. Acute hydrocephalus was rare, and ventricular drainage was needed in only four cases. Intracranial pressure (ICP) was elevated (> 15 mm Hg) in 46% of patients. The amount of IVH was related inversely with the Glasgow Coma Scale, but not with increased ICP. The presence of IVH indicated a poor outcome, with only half of the patients being independent at a 6-month follow-up. Poor outcome was associated with increasing age, low admission Glasgow Coma Scale, the presence of space occupying lesions if only the lateral ventricles were involved, and hemorrhage in all four ventricles.(ABSTRACT TRUNCATED AT 250 WORDS)

Observer variability in assessing lumbar spinal stenosis severity on magnetic resonance imaging and its relation to cross-sectional spinal canal area.

Study Design. Magnetic resonance image grading of lumbar spinal stenosis severity was analyzed retrospectively using a common clinical format. Objective. To assess the interobserver and intraobserver reliability of magnetic resonance image used to grade patients with lumbar spinal stenosis, as compared with cross-sectional spinal canal area. Summary of Background Data. Physicians currently classify the degree of lumbar spinal stenosis on magnetic resonance imaging as mild, moderate, or severe. Unfortunately, there is no consensus on criteria for these definitions. Methods. The magnetic resonance image scans of 15 patients with lumbar stenosis were blindly rated by seven observers for the degree of central, lateral recess, and foraminal stenosis between L1–L2 and L5–S1. Weighted kappa statistics were performed to analyze the inter- and intraobserver agreement. Digitized spinal canal area measurements were calculated. Linear regression models were used to assess the reliability of the grading system in predicting the cross-sectional area. Results. The average interobserver kappa score was 0.26. Within different specialties, the interobserver reliability was higher among radiologists (0.40), followed by neurosurgeons (0.21) and orthopedic surgeons (0.15). The average intraobserver kappa score was 0.11, rising to 0.43 after categories were combined (P = 0.001). The classification of central stenosis highly predicted spinal canal area (P < 0.001). Conclusions. The findings indicate only a fair level of agreement among all observers. However, the ability of the various readers to predict the degree of central stenosis was high. Further studies should evaluate a consensus-based, standardized magnetic resonance image classification aimed at improved agreement among observers.