Charles Wilson - Academia.edu (original) (raw)
Papers by Charles Wilson
Journal of Neurosurgery, 1972
... Takao Hoshino, MD, Marvin Barker, MS, Charles B. Wilson, MD, Edwin B. Boldrey, MD, and Derek ... more ... Takao Hoshino, MD, Marvin Barker, MS, Charles B. Wilson, MD, Edwin B. Boldrey, MD, and Derek Fewer, MD. HC Naffziger Laboratories for Neurosurgical Research, Department of Neurological ... Winawer SJ, Lipkin M: Cell proliferation kinetics in the gastrointestinal tract of man. ...
The paper investigates how a competitive market would allocate insurance policies if firms were n... more The paper investigates how a competitive market would allocate insurance policies if firms were not able to determine the riskiness of individual consumers. It is demonstrated that if all firms have static expectations with regard to the policy offers of other firms, no stationary equilibrium may exist. A second equilibrium concept is then introduced which incorporates a different expectation rule. Each firm assumes that any policy will be immediately withdrawn which becomes unprofitable after that firm makes its own policy offer. This equilibrium is shown to exist and some of its welfare properties are investigated.
Journal of Neurosurgery, 1988
The authors believe that the preferred treatment for pineal region tumors in children requires de... more The authors believe that the preferred treatment for pineal region tumors in children requires definitive surgery with a histological diagnosis and that a conservative approach consisting of shunting and radiation therapy no longer seems to be appropriate. The results are reported of a retrospective review of the presentation, treatment, and outcome of 36 children under the age of 18 years treated between 1974 and 1986. Eleven children had germinomas (two-cell type), seven had astrocytomas, and the remaining 18 had 15 histologically different tumor types. Surgery was performed on 30 patients; there were no deaths, but a 10% rate of persistent morbidity was found. The median follow-up period was 4 years. Nine (82%) of 11 patients with germinomas are alive without evidence of recurrence; one child died from recurrent tumor in the pineal region and another is presently being treated for recurrent tumor of the spinal cord. Six (86%) of the seven patients with astrocytoma are well after biopsy and radiation therapy. Of the remaining 18 children, five (28%) died from tumor progression. The cerebrospinal fluid (CSF) tumor markers alpha-fetoprotein and beta-human chorionic gonadotropin were helpful in determining the presence of malignant germ-cell tumors, particularly those with a poor prognosis. Magnetic resonance imaging was useful for diagnosis and for planning the operative approach. Magnetic resonance images showed the presence of pineal region tumors in four children with hydrocephalus who had no evidence of tumor on computerized tomography scans. Because the great variety of tumor types found in the pineal region must be treated in different ways and because improved microsurgical and stereotaxic surgical techniques have made mortality and morbidity rates acceptably low, a biopsy diagnosis should be obtained in all patients. Preoperative assessment of CSF tumor markers and cytology is useful for the identification of patients who have a poor prognosis.
Journal of Neurosurgery, 1986
The clinical and radiographic findings, surgical treatment, and outcome in 16 pediatric patients ... more The clinical and radiographic findings, surgical treatment, and outcome in 16 pediatric patients with intracranial arachnoid cysts are reviewed. The clinical presentation reflected the anatomical location of the lesions. Computerized tomography or magnetic resonance imaging scans were diagnostic in all cases. Of the nine cysts treated primarily or secondarily by craniotomy for fenestration and drainage into the basilar cisterns, five recurred. Cyst-peritoneal shunting led to diminished cyst size and clinical improvement in all seven cases in which it was used as the initial treatment and in all four cases in which fenestration had been unsuccessful. The results in this series show that cyst-peritoneal shunting is the treatment of choice for most intracranial arachnoid cysts in children.
Journal of Neurosurgery, 1978
In a series of 250 pituitary adenomas, 72 (28.8%) were nonsecreting and 178 (71.2%) produced a hy... more In a series of 250 pituitary adenomas, 72 (28.8%) were nonsecreting and 178 (71.2%) produced a hypersecretion syndrome: human growth hormone (83), prolactin (59), and adrenocorticotropic hormone (ACTH) (36). One-fifth had received prior treatment and one-fourth had visual impairment. The technical aspects of the transsphenoidal procedure are given with separate consideration of microadenomas and larger tumors. The results are provided in summary form with emphasis on the favorable outcome following removal of microadenomas. There was one postoperative death, and the complications observed after operation are presented.
Journal of Neurosurgery, 1994
The authors retrospectively analyzed 140 patients treated at the University of California, San Fr... more The authors retrospectively analyzed 140 patients treated at the University of California, San Francisco, from 1967 to 1990 to evaluate the results of radiation therapy (median 5400 cGy) given as an adjuvant to subtotal resection of intracranial meningioma. Of the 140 meningiomas, 117 were benign and 23 were malignant. The median follow-up period was 40 months. The overall survival rate at 5 years was 85% for the benign and 58% for the malignant tumor groups (p = 0.02); the 5-year progression-free survival rates were 89% and 48%, respectively (p = 0.001). For patients with benign meningioma, the 10-year overall and progression-free survival rates were 77%. An improved progression-free survival rate in that group was not related to tumor size but was associated with a younger age (p = 0.01) and treatment after 1980 with innovative technologies (p = 0.002); none of those variables affected the progression-free survival rate in the patients with malignant meningioma. Increased progression-free survival in the benign tumor group was also significantly associated with increasing the minimum radiation dose (p = 0.04). The 5-year progression-free survival rate for patients with benign meningioma treated after 1980 (when computerized tomography or magnetic resonance imaging was used for planning therapy) was 98%, as compared with 77% for patients treated before 1980 (p = 0.002). There were no second central nervous system tumors. Morbidity (3.6%) included sudden blindness or cerebral necrosis and death. When total resection of benign meningioma is not feasible, subtotal resection combined with precise treatment planning techniques and adjuvant radiation therapy can achieve results comparable to those of total resection.
Water Resources Research, 1979
AbstractThis study is an assessment of the importance of precipitation accuracy on the rainfall-r... more AbstractThis study is an assessment of the importance of precipitation accuracy on the rainfall-runoff modeling of a small catchment. Two mathematical models were used in the investigation: a deterministic rainfall-runoff model based on the kinematic wave approximation and a nonstationary time-varying multidimensional rainfall generation model. It is implicitly assumed that this rainfall generation model is an appropriate mathematical representation of the natural phenomenon of rainfall. The deterministic rainfall-runoff model is used to represent the 26.5-mi2 catchment of the Rio Fajardo in northeastern Puerto Rico. The rainfall model generates synthetic rainfall which serves as the input to this runoff model. The influence of the spatial distribution of the rainfall input on the discharge is analyzed by using 1 rain gage or 20 rain gages to record the synthetic storms. The isohyetal maps and hyetographs of the synthetic storms, together with the storm hydrographs produced by the runoff model, are analyzed, with specific attention given to the volume of storm runoff, time-to-peak runoff, and peak runoff. The experiments show that the spatial distribution of rain and the accuracy of the precipitation input have a marked influence on the outflow hydrograph from a small catchment.
Journal of Neurosurgery, 1989
This study includes 182 patients with intracranial gliomas who received bromodeoxyuridine (BUdR),... more This study includes 182 patients with intracranial gliomas who received bromodeoxyuridine (BUdR), 200 mg/sq m intravenously, at the time of craniotomy but before tumor biopsy. The tumor specimens were stained for BUdR using the immunoperoxidase method; the BUdR labeling index (LI), or S-phase fraction, was calculated as the percentage of BUdR-positive cells. The median BUdR LI's for 127 primary moderately anaplastic astrocytomas, highly anaplastic astrocytomas, and glioblastomas (less than 1%, 2.7%, and 7.3%, respectively; range 0% to 38.1%) were not significantly different from those of 55 similar recurrent tumors (less than 1%, 4.3%, and 7.4%, respectively; range 0% to 30.5%). The mean LI was significantly higher in tumors from patients over 50 years of age than in tumors from younger patients (p less than 0.001). The age-related difference in LI's was found in both groups of patients with astrocytomas but not in those with glioblastomas. Kaplan-Meier survival curves showed a significantly greater probability of survival among patients whose tumors had LI's of less than 1% than among those with LI's greater than 5%; survival probability of patients with tumor LI's of 1% to 5% was intermediate between the two extremes. Thus, the BUdR LI appears to reflect the proliferative potential more accurately than the histopathological diagnosis and should therefore be considered an important factor in determining the prognosis of individual patients with intracranial gliomas and in selecting their treatment.
Cancer, 1974
... Horace Norrell MD †,* ,; Charles B. Wilson MD ‡ ,; Donald E. Slagel PHD § ,; David B. Clark M... more ... Horace Norrell MD †,* ,; Charles B. Wilson MD ‡ ,; Donald E. Slagel PHD § ,; David B. Clark MD, PHD ¶. ... Lancet i: 249–250, 1970. CrossRef. 40 Rubin, RC, Ommaya, AK, Henderson, ES, Bering, EA, and Rall, DP: Cerebrospinal fluid perfusion for central nervous system neoplasms ...
Journal of Neurosurgery, 1986
To determine the percentage of patients who developed multiple central nervous system (CNS) gliom... more To determine the percentage of patients who developed multiple central nervous system (CNS) gliomas during postoperative radiation therapy and chemotherapy, the authors reviewed the records of 1047 patients treated between December 2, 1976, and August 16, 1985, who had an original diagnosis of supratentorial glioblastoma multiforme or other anaplastic glioma. The occurrence of multiple lesions was verified by neurodiagnostic studies (computerized tomography or myelography) or by findings at operation or autopsy. Twelve patients (1.1%) who presented with multiple lesions were excluded from this analysis. There were 405 patients with glioblastoma multiforme; their median age was 46.5 years (range 22 to 70 years). Eighteen (5%) of these patients had multiple CNS lesions, five of which were in the spinal cord. The median time from diagnosis to detection of the second lesion in this group was 59.5 weeks (range 10 to 182 weeks). There were 630 patients with anaplastic glioma (which included mixed malignant glioma and highly anaplastic, gemistocytic, moderately anaplastic, and anaplastic astrocytomas); their median age was 30 years (range 2 to 62 years). Fifty-four (8.6%) of these patients had multiple lesions, 10 of which were in the spinal cord; only one case of extraneural metastasis was found. The median time from diagnosis to detection of the second lesion in this group was 101 weeks (range 14 to 459 weeks). These results show that more than 90% of CNS gliomas recur at the site of the original tumor. Considering the high frequency of intellectual dysfunction after whole-brain radiation therapy, the use of focal radiation fields appears to be the most judicious approach to the treatment of patients with gliomas.
International Journal of Radiation Oncology Biology Physics, 1990
Journal of Neurosurgery, 1993
Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involvi... more Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.
Journal of Neurosurgery, 1978
A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitroso... more A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and/or radiotherapy in the treatment of patients who were operated on and had histological confirmation of anaplastic glioma. A total of 303 patients were randomized into this study, of whom 222 (73%) were within the Valid Study Group (VSG), having met the protocol criteria of neuropathology, corticosteroid control, and therapeutic approach. Patients were divided into four random groups, and received BCNU (80 mg/sq m/day on 3 successive days every 6 to 8 weeks), and/or radiotherapy (5000 to 6000 rads to the whole brain through bilateral opposing ports), or best conventional care but no chemotherapy or radiotherapy. Analysis was performed on all patients who received any amount of therapy (VSG) and on the Adequately Treated Group (ATG), who had received 5000 or more rads radiotherapy, two or more courses of chemotherapy, and had a minimum survival of 8 or more weeks (the interval that would have been required to have received either the radiotherapy or chemotherapy). Median survival of patients in the VSG was, best conventional care: 14 weeks (ATG: 17.0 weeks); BCNU: 18.5 weeks (ATG: 25.0 weeks); radiotherapy: 35 weeks (ATG: 37.5 weeks); and BCNU plus radiotherapy: 34.5 weeks (ATG: 40.5 weeks). All therapeutic modalities showed some statistical superiority compared to best conventional care. There was no significant difference between the four groups in relation to age distribution, sex, location of tumor, diagnosis, tumor characteristics, signs or symptoms, or the amount of corticosteroid used. An analysis of prognostic factors indicates that the initial performance status (Karnofsky rating), age, the use of only a surgical biopsy, parietal location, the presence of seizures, or the involvement of cranial nerves II, III, IV, and VI are all of significance. Toxicity included acceptable, reversible thrombocytopenia and leukopenia.
Journal of Neurosurgery, 1990
Neuron, 1997
The hippocampus and its associated structures play a key role in human memory, yet the underlying... more The hippocampus and its associated structures play a key role in human memory, yet the underlying neuronal mechanisms remain unknown. Here, we report that during encoding and recognition, single neurons in the medial temporal lobe discriminated faces from inanimate objects. Some units responded selectively to specific emotional expressions or to conjunctions of facial expression and gender. Such units were especially prevalent during recognition, and the responses depended on stimulus novelty or familiarity. Traces of exposure to faces or objects were found a few seconds after stimulus removal as well as 10 hr later. Some neurons maintained a record of previous stimulus presentation that was more accurate than the person's conscious recollection. We propose that the human medial temporal lobe constructs a “cognitive map” of stimulus attributes comparable to the map of the spatial environment described in the rodent hippocampus.
Epilepsia, 1999
Summary: Purpose: Properties of oscillations with frequencies >100 Hz were studied in kainic acid... more Summary: Purpose: Properties of oscillations with frequencies >100 Hz were studied in kainic acid (KA)-treated rats and compared with those recorded in normal and kindled rats as well as in patients with epilepsy to determine differences associated with epilepsy.Methods: Prolonged in vivo wideband recordings of electrical activity were made in hippocampus and entorhinal cortex (EC) of (a) normal rats, (b) kindled rats, (c) rats having chronic recurrent spontaneous seizures after intrahippocampal KA injections, and (d) patients with epilepsy undergoing depth electrode evaluation in preparation for surgical treatment.Results: Intermittent oscillatory activity ranging from 100 to 200 Hz in frequency and 50–150 ms in duration was recorded in CA1 and EC of all three animal groups, and in epileptic human hippocampus and EC. This activity had the same characteristics in all groups, resembled previously observed “ripples” described by Buzsáki et al., and appeared to represent field potentials of inhibitory postsynaptic potentials (IPSPs) on principal cells. Unexpectedly, higher frequency intermittent oscillatory activity ranging from 200 to 500 Hz and 10–100 ms in duration was encountered only in KA-treated rats and patients with epilepsy. These oscillations, termed fast ripples (FRs), were found only adjacent to the epileptogenic lesion in hippocampus, EC, and dentate gyrus, and appeared to represent field potential population spikes. Their local origin was indicated by correspondence with the negative phase of burst discharges of putative pyramidal cells.Conclusions: The persistence of normal-appearing ripples in epileptic brain support the view that inhibitory processes are preserved. FRs appear to be field potentials reflecting hypersynchronous bursting of excitatory neurons and provide an opportunity to study the role of this pathophysiologic phenomenon in epilepsy and seizure initiation. Furthermore, if FR activity is unique to brain areas capable of generating spontaneous seizures, its identification could be a powerful functional indicator of the epileptic region in patients evaluated for surgical treatment.
IEEE Computer, 2000
On the basis of media hype alone, you might conclude that biometric passwords will soon replace t... more On the basis of media hype alone, you might conclude that biometric passwords will soon replace their alphanumeric counterparts with versions that cannot be stolen, forgotten, lost, or given to another person. But what if the actual performance of these systems falls short of the estimates? The authors designed this article to provide sufficient information to know what questions to ask when evaluating a biometric system, and to assist in determining whether performance levels meet the requirements of an application. For example, a low-performance biometric is probably sufficient for reducing-as opposed to eliminating-fraud. Likewise, completely replacing an existing security system with a biometric-based one may require a high-performance biometric system, or the required performance may be beyond what current technology can provide. Of the biometrics that give the user some control over data acquisition, voice, face, and fingerprint systems have undergone the most study and testing-and therefore occupy the bulk of this discussion. This article also covers the tools and techniques of biometric testing
Journal of Neurosurgery, 1972
... Takao Hoshino, MD, Marvin Barker, MS, Charles B. Wilson, MD, Edwin B. Boldrey, MD, and Derek ... more ... Takao Hoshino, MD, Marvin Barker, MS, Charles B. Wilson, MD, Edwin B. Boldrey, MD, and Derek Fewer, MD. HC Naffziger Laboratories for Neurosurgical Research, Department of Neurological ... Winawer SJ, Lipkin M: Cell proliferation kinetics in the gastrointestinal tract of man. ...
The paper investigates how a competitive market would allocate insurance policies if firms were n... more The paper investigates how a competitive market would allocate insurance policies if firms were not able to determine the riskiness of individual consumers. It is demonstrated that if all firms have static expectations with regard to the policy offers of other firms, no stationary equilibrium may exist. A second equilibrium concept is then introduced which incorporates a different expectation rule. Each firm assumes that any policy will be immediately withdrawn which becomes unprofitable after that firm makes its own policy offer. This equilibrium is shown to exist and some of its welfare properties are investigated.
Journal of Neurosurgery, 1988
The authors believe that the preferred treatment for pineal region tumors in children requires de... more The authors believe that the preferred treatment for pineal region tumors in children requires definitive surgery with a histological diagnosis and that a conservative approach consisting of shunting and radiation therapy no longer seems to be appropriate. The results are reported of a retrospective review of the presentation, treatment, and outcome of 36 children under the age of 18 years treated between 1974 and 1986. Eleven children had germinomas (two-cell type), seven had astrocytomas, and the remaining 18 had 15 histologically different tumor types. Surgery was performed on 30 patients; there were no deaths, but a 10% rate of persistent morbidity was found. The median follow-up period was 4 years. Nine (82%) of 11 patients with germinomas are alive without evidence of recurrence; one child died from recurrent tumor in the pineal region and another is presently being treated for recurrent tumor of the spinal cord. Six (86%) of the seven patients with astrocytoma are well after biopsy and radiation therapy. Of the remaining 18 children, five (28%) died from tumor progression. The cerebrospinal fluid (CSF) tumor markers alpha-fetoprotein and beta-human chorionic gonadotropin were helpful in determining the presence of malignant germ-cell tumors, particularly those with a poor prognosis. Magnetic resonance imaging was useful for diagnosis and for planning the operative approach. Magnetic resonance images showed the presence of pineal region tumors in four children with hydrocephalus who had no evidence of tumor on computerized tomography scans. Because the great variety of tumor types found in the pineal region must be treated in different ways and because improved microsurgical and stereotaxic surgical techniques have made mortality and morbidity rates acceptably low, a biopsy diagnosis should be obtained in all patients. Preoperative assessment of CSF tumor markers and cytology is useful for the identification of patients who have a poor prognosis.
Journal of Neurosurgery, 1986
The clinical and radiographic findings, surgical treatment, and outcome in 16 pediatric patients ... more The clinical and radiographic findings, surgical treatment, and outcome in 16 pediatric patients with intracranial arachnoid cysts are reviewed. The clinical presentation reflected the anatomical location of the lesions. Computerized tomography or magnetic resonance imaging scans were diagnostic in all cases. Of the nine cysts treated primarily or secondarily by craniotomy for fenestration and drainage into the basilar cisterns, five recurred. Cyst-peritoneal shunting led to diminished cyst size and clinical improvement in all seven cases in which it was used as the initial treatment and in all four cases in which fenestration had been unsuccessful. The results in this series show that cyst-peritoneal shunting is the treatment of choice for most intracranial arachnoid cysts in children.
Journal of Neurosurgery, 1978
In a series of 250 pituitary adenomas, 72 (28.8%) were nonsecreting and 178 (71.2%) produced a hy... more In a series of 250 pituitary adenomas, 72 (28.8%) were nonsecreting and 178 (71.2%) produced a hypersecretion syndrome: human growth hormone (83), prolactin (59), and adrenocorticotropic hormone (ACTH) (36). One-fifth had received prior treatment and one-fourth had visual impairment. The technical aspects of the transsphenoidal procedure are given with separate consideration of microadenomas and larger tumors. The results are provided in summary form with emphasis on the favorable outcome following removal of microadenomas. There was one postoperative death, and the complications observed after operation are presented.
Journal of Neurosurgery, 1994
The authors retrospectively analyzed 140 patients treated at the University of California, San Fr... more The authors retrospectively analyzed 140 patients treated at the University of California, San Francisco, from 1967 to 1990 to evaluate the results of radiation therapy (median 5400 cGy) given as an adjuvant to subtotal resection of intracranial meningioma. Of the 140 meningiomas, 117 were benign and 23 were malignant. The median follow-up period was 40 months. The overall survival rate at 5 years was 85% for the benign and 58% for the malignant tumor groups (p = 0.02); the 5-year progression-free survival rates were 89% and 48%, respectively (p = 0.001). For patients with benign meningioma, the 10-year overall and progression-free survival rates were 77%. An improved progression-free survival rate in that group was not related to tumor size but was associated with a younger age (p = 0.01) and treatment after 1980 with innovative technologies (p = 0.002); none of those variables affected the progression-free survival rate in the patients with malignant meningioma. Increased progression-free survival in the benign tumor group was also significantly associated with increasing the minimum radiation dose (p = 0.04). The 5-year progression-free survival rate for patients with benign meningioma treated after 1980 (when computerized tomography or magnetic resonance imaging was used for planning therapy) was 98%, as compared with 77% for patients treated before 1980 (p = 0.002). There were no second central nervous system tumors. Morbidity (3.6%) included sudden blindness or cerebral necrosis and death. When total resection of benign meningioma is not feasible, subtotal resection combined with precise treatment planning techniques and adjuvant radiation therapy can achieve results comparable to those of total resection.
Water Resources Research, 1979
AbstractThis study is an assessment of the importance of precipitation accuracy on the rainfall-r... more AbstractThis study is an assessment of the importance of precipitation accuracy on the rainfall-runoff modeling of a small catchment. Two mathematical models were used in the investigation: a deterministic rainfall-runoff model based on the kinematic wave approximation and a nonstationary time-varying multidimensional rainfall generation model. It is implicitly assumed that this rainfall generation model is an appropriate mathematical representation of the natural phenomenon of rainfall. The deterministic rainfall-runoff model is used to represent the 26.5-mi2 catchment of the Rio Fajardo in northeastern Puerto Rico. The rainfall model generates synthetic rainfall which serves as the input to this runoff model. The influence of the spatial distribution of the rainfall input on the discharge is analyzed by using 1 rain gage or 20 rain gages to record the synthetic storms. The isohyetal maps and hyetographs of the synthetic storms, together with the storm hydrographs produced by the runoff model, are analyzed, with specific attention given to the volume of storm runoff, time-to-peak runoff, and peak runoff. The experiments show that the spatial distribution of rain and the accuracy of the precipitation input have a marked influence on the outflow hydrograph from a small catchment.
Journal of Neurosurgery, 1989
This study includes 182 patients with intracranial gliomas who received bromodeoxyuridine (BUdR),... more This study includes 182 patients with intracranial gliomas who received bromodeoxyuridine (BUdR), 200 mg/sq m intravenously, at the time of craniotomy but before tumor biopsy. The tumor specimens were stained for BUdR using the immunoperoxidase method; the BUdR labeling index (LI), or S-phase fraction, was calculated as the percentage of BUdR-positive cells. The median BUdR LI's for 127 primary moderately anaplastic astrocytomas, highly anaplastic astrocytomas, and glioblastomas (less than 1%, 2.7%, and 7.3%, respectively; range 0% to 38.1%) were not significantly different from those of 55 similar recurrent tumors (less than 1%, 4.3%, and 7.4%, respectively; range 0% to 30.5%). The mean LI was significantly higher in tumors from patients over 50 years of age than in tumors from younger patients (p less than 0.001). The age-related difference in LI's was found in both groups of patients with astrocytomas but not in those with glioblastomas. Kaplan-Meier survival curves showed a significantly greater probability of survival among patients whose tumors had LI's of less than 1% than among those with LI's greater than 5%; survival probability of patients with tumor LI's of 1% to 5% was intermediate between the two extremes. Thus, the BUdR LI appears to reflect the proliferative potential more accurately than the histopathological diagnosis and should therefore be considered an important factor in determining the prognosis of individual patients with intracranial gliomas and in selecting their treatment.
Cancer, 1974
... Horace Norrell MD †,* ,; Charles B. Wilson MD ‡ ,; Donald E. Slagel PHD § ,; David B. Clark M... more ... Horace Norrell MD †,* ,; Charles B. Wilson MD ‡ ,; Donald E. Slagel PHD § ,; David B. Clark MD, PHD ¶. ... Lancet i: 249–250, 1970. CrossRef. 40 Rubin, RC, Ommaya, AK, Henderson, ES, Bering, EA, and Rall, DP: Cerebrospinal fluid perfusion for central nervous system neoplasms ...
Journal of Neurosurgery, 1986
To determine the percentage of patients who developed multiple central nervous system (CNS) gliom... more To determine the percentage of patients who developed multiple central nervous system (CNS) gliomas during postoperative radiation therapy and chemotherapy, the authors reviewed the records of 1047 patients treated between December 2, 1976, and August 16, 1985, who had an original diagnosis of supratentorial glioblastoma multiforme or other anaplastic glioma. The occurrence of multiple lesions was verified by neurodiagnostic studies (computerized tomography or myelography) or by findings at operation or autopsy. Twelve patients (1.1%) who presented with multiple lesions were excluded from this analysis. There were 405 patients with glioblastoma multiforme; their median age was 46.5 years (range 22 to 70 years). Eighteen (5%) of these patients had multiple CNS lesions, five of which were in the spinal cord. The median time from diagnosis to detection of the second lesion in this group was 59.5 weeks (range 10 to 182 weeks). There were 630 patients with anaplastic glioma (which included mixed malignant glioma and highly anaplastic, gemistocytic, moderately anaplastic, and anaplastic astrocytomas); their median age was 30 years (range 2 to 62 years). Fifty-four (8.6%) of these patients had multiple lesions, 10 of which were in the spinal cord; only one case of extraneural metastasis was found. The median time from diagnosis to detection of the second lesion in this group was 101 weeks (range 14 to 459 weeks). These results show that more than 90% of CNS gliomas recur at the site of the original tumor. Considering the high frequency of intellectual dysfunction after whole-brain radiation therapy, the use of focal radiation fields appears to be the most judicious approach to the treatment of patients with gliomas.
International Journal of Radiation Oncology Biology Physics, 1990
Journal of Neurosurgery, 1993
Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involvi... more Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.
Journal of Neurosurgery, 1978
A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitroso... more A controlled, prospective, randomized study evaluated the use of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and/or radiotherapy in the treatment of patients who were operated on and had histological confirmation of anaplastic glioma. A total of 303 patients were randomized into this study, of whom 222 (73%) were within the Valid Study Group (VSG), having met the protocol criteria of neuropathology, corticosteroid control, and therapeutic approach. Patients were divided into four random groups, and received BCNU (80 mg/sq m/day on 3 successive days every 6 to 8 weeks), and/or radiotherapy (5000 to 6000 rads to the whole brain through bilateral opposing ports), or best conventional care but no chemotherapy or radiotherapy. Analysis was performed on all patients who received any amount of therapy (VSG) and on the Adequately Treated Group (ATG), who had received 5000 or more rads radiotherapy, two or more courses of chemotherapy, and had a minimum survival of 8 or more weeks (the interval that would have been required to have received either the radiotherapy or chemotherapy). Median survival of patients in the VSG was, best conventional care: 14 weeks (ATG: 17.0 weeks); BCNU: 18.5 weeks (ATG: 25.0 weeks); radiotherapy: 35 weeks (ATG: 37.5 weeks); and BCNU plus radiotherapy: 34.5 weeks (ATG: 40.5 weeks). All therapeutic modalities showed some statistical superiority compared to best conventional care. There was no significant difference between the four groups in relation to age distribution, sex, location of tumor, diagnosis, tumor characteristics, signs or symptoms, or the amount of corticosteroid used. An analysis of prognostic factors indicates that the initial performance status (Karnofsky rating), age, the use of only a surgical biopsy, parietal location, the presence of seizures, or the involvement of cranial nerves II, III, IV, and VI are all of significance. Toxicity included acceptable, reversible thrombocytopenia and leukopenia.
Journal of Neurosurgery, 1990
Neuron, 1997
The hippocampus and its associated structures play a key role in human memory, yet the underlying... more The hippocampus and its associated structures play a key role in human memory, yet the underlying neuronal mechanisms remain unknown. Here, we report that during encoding and recognition, single neurons in the medial temporal lobe discriminated faces from inanimate objects. Some units responded selectively to specific emotional expressions or to conjunctions of facial expression and gender. Such units were especially prevalent during recognition, and the responses depended on stimulus novelty or familiarity. Traces of exposure to faces or objects were found a few seconds after stimulus removal as well as 10 hr later. Some neurons maintained a record of previous stimulus presentation that was more accurate than the person's conscious recollection. We propose that the human medial temporal lobe constructs a “cognitive map” of stimulus attributes comparable to the map of the spatial environment described in the rodent hippocampus.
Epilepsia, 1999
Summary: Purpose: Properties of oscillations with frequencies >100 Hz were studied in kainic acid... more Summary: Purpose: Properties of oscillations with frequencies >100 Hz were studied in kainic acid (KA)-treated rats and compared with those recorded in normal and kindled rats as well as in patients with epilepsy to determine differences associated with epilepsy.Methods: Prolonged in vivo wideband recordings of electrical activity were made in hippocampus and entorhinal cortex (EC) of (a) normal rats, (b) kindled rats, (c) rats having chronic recurrent spontaneous seizures after intrahippocampal KA injections, and (d) patients with epilepsy undergoing depth electrode evaluation in preparation for surgical treatment.Results: Intermittent oscillatory activity ranging from 100 to 200 Hz in frequency and 50–150 ms in duration was recorded in CA1 and EC of all three animal groups, and in epileptic human hippocampus and EC. This activity had the same characteristics in all groups, resembled previously observed “ripples” described by Buzsáki et al., and appeared to represent field potentials of inhibitory postsynaptic potentials (IPSPs) on principal cells. Unexpectedly, higher frequency intermittent oscillatory activity ranging from 200 to 500 Hz and 10–100 ms in duration was encountered only in KA-treated rats and patients with epilepsy. These oscillations, termed fast ripples (FRs), were found only adjacent to the epileptogenic lesion in hippocampus, EC, and dentate gyrus, and appeared to represent field potential population spikes. Their local origin was indicated by correspondence with the negative phase of burst discharges of putative pyramidal cells.Conclusions: The persistence of normal-appearing ripples in epileptic brain support the view that inhibitory processes are preserved. FRs appear to be field potentials reflecting hypersynchronous bursting of excitatory neurons and provide an opportunity to study the role of this pathophysiologic phenomenon in epilepsy and seizure initiation. Furthermore, if FR activity is unique to brain areas capable of generating spontaneous seizures, its identification could be a powerful functional indicator of the epileptic region in patients evaluated for surgical treatment.
IEEE Computer, 2000
On the basis of media hype alone, you might conclude that biometric passwords will soon replace t... more On the basis of media hype alone, you might conclude that biometric passwords will soon replace their alphanumeric counterparts with versions that cannot be stolen, forgotten, lost, or given to another person. But what if the actual performance of these systems falls short of the estimates? The authors designed this article to provide sufficient information to know what questions to ask when evaluating a biometric system, and to assist in determining whether performance levels meet the requirements of an application. For example, a low-performance biometric is probably sufficient for reducing-as opposed to eliminating-fraud. Likewise, completely replacing an existing security system with a biometric-based one may require a high-performance biometric system, or the required performance may be beyond what current technology can provide. Of the biometrics that give the user some control over data acquisition, voice, face, and fingerprint systems have undergone the most study and testing-and therefore occupy the bulk of this discussion. This article also covers the tools and techniques of biometric testing