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Biomedical subjects

E R Laws

Publications and source records attributed to E R Laws.

At least 127 records · Page 7Linked to original sources
PubMed1991

Individual C6 glioma cells migrate in adult rat brain after neural homografting.

Cultured C6 glioma cells were prelabeled with the plant lectin Phaseolus vulgaris leuco-agglutinin (PHAL) and grafted as a cell suspension (10(6) cells in 5.0 microliters) into freshly made cortical implantation pockets in adult host rats. Animals were killed 1-21 days post-implantation (DPI). The brains were removed, dehydrated, embedded in paraffin and sectioned at 8 microns. Paraffin sections were processed for light level immunofluorescent double labeling for PHAL, a marker for graft derived cells, and glial fibrillary acidic protein (GFAP), a specific marker for C6 glioma cells and astrocytes. Cells positive for both PHAL and GFAP were graft-derived C6 cells. By 7 DPI a large mass developed which extended above the surface of the brain and invaded (displacement of host tissue by a cell mass) the host parenchyma. This mass increased in size over the next 14 days. The invading tumor mass contained double labeled cells at all time periods examined. In addition to the invasion process, grafted C6 cells spread through the host parenchyma by migration (movement of single cells). Individual graft-derived C6 (GFAP/PHAL positive) cells migrated into host cortex surrounding the implantation pocket, corpus callosum ventral to the implantation pocket, ipsilateral internal capsule and bilaterally in the habenula.

Animals↗
PubMed1991

The history of the neurosurgical engine.

The opening of the skull of a living human being dates back to early civilization. The procedure may have been performed as early as the Neolithic period. Surgeons have continued to search for a better, easier, quicker, and safer method to open the skull. Today, most neurosurgeons are well acquainted with the surgical drill; however, few are familiar with the development of this instrument from its beginnings in dentistry to its use in modern neurosurgery. As cerebral localization advanced in the late 19th century, so, too, did the demands for better techniques for entering the cranial cavity and exposing more extensive areas of the brain. Mechanical devices began to appear in operating theaters throughout the world. Despite the enthusiasm of its inventors, the surgical engine was used by but a few pioneer cranial surgeons. The use of a surgical engine in the operating room has become commonplace. Its presence continues to demand respect. There is no doubt that this instrument has helped advance neurosurgery. Its development and refinement are rich in history and closely parallel the development of modern neurosurgery.

History, 18th Century↗
PubMed1991

C6 glioma-astrocytoma cell and fetal astrocyte migration into artificial basement membrane: a permissive substrate for neural tumors but not fetal astrocytes.

Cortically homografted C6 glioma-astrocytoma cells both invade the rat host brain as a mass and migrate as individual cells. In contrast, fetal astrocytes derived from homografted whole pieces of fetal cortex migrate only as individual cells throughout the brain of the rat but are not capable of invasion. Our experiment explored the migratory capacity (over 7 days) of cultured purified fetal astrocytes and C6 cells after seeding 10(6) cells on a hydrated artificial basement membrane wafer (Matrigel). The artificial basement membrane wafer was not a suitable substrate for the growth of cultured fetal astrocytes. In contrast, C6 cells migrated as individual cells from the surface of the wafer into the substrate. Individual C6 cells migrated 1.8 mm in the first 4 days and then ceased migration. The C6 cells were observed at the base of a digestion tube that extended from and was open to the surface of the wafer. At 3 days, micropockets were observed to form around each C6 cell at the base of each tube. By 7 days, the majority of pockets observed were large and contained several C6 cells. These multiple cell groups appeared to be progenitors of tumor masses. These data indicate that C6 glioma-astrocytoma cells, which in vivo appear to be a model for glioblastoma multiforme, primarily migrate as individual cells through artificial basement membrane and secondarily form tumor masses. Progenitor tumor masses form by coalescence of individual C6 cell micropockets or the division of a single cell in an individual micropocket.

Animals↗
PubMed1991

Free radical-induced injury to C6 glioma cells.

Scanning electron microscopic studies revealed that the cell bodies of cultured C6 cells were densely covered with villi and that membrane blebs were rare. Exposure to a hydroxyl radical generating system resulted in rapid ultrastructural changes. Within 2.5 minutes, 98% of the cells lost their villi. The number of blebbed cells increased during the first 7.5 minutes of exposure, until virtually all cells were blebbed. After 20 and 30 minutes of exposure, the plasma membrane of the blebs ruptured, resulting in the escape of cell contents and cell necrosis. Trypan blue exclusion, a measure of cell viability, decreased between 1 and 7.5 minutes of exposure. No further significant decline in viability was observed for the remainder of the experiment. The hydroxyl radical generating system also initiated a rapid onset of membrane lipid peroxidation, as measured by accumulation of thiobarbiturate reactive material. After a short lag period, thiobarbiturate reactive material increased rapidly, with maximum lipid peroxidation occurring by 20 minutes. Increasing the concentration of the radical generating system components shortened the time course but not the level of maximal thiobarbiturate reactive material production. These data suggest that plasmalemmal lipid peroxidation plays a role in rapid morphological changes and necrosis that occur after free radical insult.

Animals↗
PubMed1990

Radiotherapeutic considerations in the treatment of hemangioblastomas of the central nervous system.

Twenty-seven hemangioblastomas of the central nervous system were treated at the Mayo Clinic with radiation therapy from January 1963 to August 1983. Six patients had von-Hippel Lindau syndrome, and four presented with polycythemia. The median age among the 15 males and 12 females was 48 years (range 20-68). Two clinical groups were apparent: those that received postoperative radiation therapy for clinically suspect, or microscopically positive margins (6 patients) and those who underwent therapy for gross residual disease (20 patients). One patient did not fall into either group because his initially unresectable tumor was treated with planned pre-operative radiotherapy to 40 Gy and was subsequently successfully cured by surgery. Because the combined modality approach did not allow assessment of local control with radiation alone, he was excluded from the gross residual cohort in terms of time-dose relationship analysis. The cohort with gross residual disease was particularly unfavorable as 12 of these patients had developed 17 local recurrences prior to radiation. Three had multiple lesions, and four had the von-Hippel Lindau syndrome. In-field disease control appeared to be improved when patients were treated more aggressively. Patients treated to a dose of 50 Gy manifested local control in 4/7 (57%) vs 4/12 (33%) in patients treated to less than 50 Gy. In-field local control was also better if patients received a TDF greater than 75 (local control in 66%) vs a TDF of 65-75 (local control in 22%). Actuarial analysis of in-field disease control showed more aggressive treatment improved control whether analyzed by dose level (greater than or equal to 50 Gy vs less than 50 Gy, or TDF greater than 75 vs less than 75). Four of the six patients who received radiation therapy for microscopically positive or clinically suspect margins achieved local control. Both patients manifesting in-field relapse were successfully surgically salvaged. Overall survival for the entire group of 27 patients was 85%, 58%, 58%, and 46% at 5, 10, 15, and 20 years, respectively. Recurrence-free survival was 76%, 52%, and 42% at 5, 10, and 15 years, respectively. Half of all in-field recurrences had occurred by 2 years, but the remaining half recurred from 5.6 to 14.4 years. Patients who developed in-field failure usually died from disease with a median survival of only 1.5 years, but surgical salvage was accomplished in 4/12. Hydro-myelia developed in two patients and required operation. Surveillance for systemic tumors also was important and revealed seven benign and four malignant tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Medulloblastoma--prognostic factors and outcome of treatment: review of the Mayo Clinic experience.

From March 1965 through December 1984, 58 patients (35 male and 23 female patients; median age, 17 years) with posterior fossa (PF) medulloblastoma underwent surgical treatment and postoperative radiation therapy at our institution. Radiation fields were the craniospinal axis in 39 patients, PF plus spinal axis in 12, PF in 6, and whole brain in 1. Median radiation doses were 43 Gy (22 to 60 Gy) to the PF and 34 Gy (6.2 to 50 Gy) to the spinal axis. Overall 5- and 10-year survivals were 50% and 33%, respectively; 5- and 10-year relapse-free survivals were 46% and 32%. Treatment failed in 34 patients (59%): in 18 who had irradiation to the craniospinal axis (13 had received 50 Gy or less to the PF) and in 16 who had a radiation field of less than the craniospinal axis. A statistically significant (P less than 0.05) improvement in 10-year survival was associated with the following prognostic variables: PF dose of 50 Gy or more, whole-brain irradiation, and spinal axis irradiation. In comparison with subtotal resection, total resection was correlated with better 10-year relapse-free survival but not overall survival. All five patients with initial treatment failure only in the spine had received a radiation dose of 30 Gy or less to the spinal axis. The 2-year survival after relapse was 46% with salvage chemotherapy or irradiation in 23 patients and 0% in the 11 patients who received no further treatment (P less than 0.01).

Adolescent↗
PubMed1990

C6 glioma cell invasion and migration of rat brain after neural homografting: ultrastructure.

C6 tumor cells (10(6] were grafted as suspensions into freshly made implantation pockets in rat host cerebral cortex. Specimens were prepared for transmission and scanning electron microscopy 1 to 7 days postimplantation (DPI). By 3 DPI vacuolated C6 cells had migrated on or invaded the host brain. C6 cells were observed on the glia limitans on the surface of the brain, in the corpus callosum, subependymal space, and perivascular space and had invaded the cortex under the implantation pocket. In addition to the tumor mass that was observed under the implantation pocket, by 7 DPI individual C6 cells had migrated into the corpus callosum and internal capsule. Migrated C6 cells were observed in a perineuronal position in the hippocampus and other gray matter structures inferior to the corpus callosum. Micropockets were found around each C6 cell and the processes of these cells had replaced host parenchyma. The preferred routes of migration were on basal lamina and parallel and intersecting nerve fiber bundles. Invasion occurred through gray and white matter. The movement of homografted C6 cells in the brain suggests that these cells actively migrate as individual cells in addition to invading as a mass.

Animals↗
PubMed1990

Transseptal approaches for pituitary surgery.

Our experience with over 147 operations for pituitary disease has given us an opportunity to use and evaluate four separate transseptal approaches. Three approaches have been described previously in the literature: the sublabial transseptal, the open rhinoplasty, and the alotomy with anterior septal dissection. The fourth approach, alotomy with posterior septal dissection, is described here. The advantages and disadvantages of each are discussed, as are the complications of transseptal surgery. A working knowledge of the various transseptal approaches to the pituitary is imperative for the otolaryngologist who participates in pituitary surgery.

Humans↗
PubMed1990

Pituitary adenomas that produce adrenocorticotropic hormone and alpha-subunit: clinicopathological, immunohistochemical, ultrastructural, and immunoelectron microscopic studies in nine cases.

Eight surgical and one autopsy specimen of pituitary adenomas (six cases of Cushing's disease, two of Nelson's syndrome, and one of hypopituitarism) were studied by histochemical, immunohistocytological, and ultrastructural methods. Eight tumors showed the characteristic histochemical profile of corticotroph adenoma--amphophilic to basophilic, and periodic acid-Schiff-positive to some extent. In all tumors, immunohistochemical studies revealed adrenocorticotropic hormone (ACTH) and alpha-subunit in the cytoplasm of some adenoma cells. By electron microscopy, seven tumors were found to be monomorphous; six were typical corticotroph adenomas and one was a subtype II silent corticotroph adenoma. One unique lesion was bimorphous--i.e., composed of corticotrophs as well as cells resembling glycoprotein cells. Immunoelectron microscopy by the double-labeling immunogold technique, performed on one corticotroph adenoma, demonstrated the presence of ACTH and alpha-subunit not only within the same adenoma cells but also within the same secretory granules. The cytogenesis of ACTH alpha-subunit tumors, a rare form of plurihormonal adenoma, remains to be elucidated. The duration of disease associated with these tumors exceeded the duration in patients with ordinary corticotroph adenomas. Given the low frequency with which increases in serum alpha-subunit are detectable in patients with such tumors--13% in this series--hormone production is not recognized at preoperative evaluation.

Adenoma↗
PubMed1990

Supratentorial low-grade gliomas.

Low-grade gliomas (grades I and II) are infiltrative lesions. Patients harboring these tumors follow extremely variable clinical courses. Review of current data suggests that in patients with large tumors, complete excision affords long-term survival, with or without radiation therapy. Partial excision should be followed by radiation therapy. The management of very small tumors in patients who are neurologically normal is controversial. Stereotactic technique is particularly useful in diagnosis, and often in tumor resection, in this group of patients.

Combined Modality Therapy↗
PubMed1990

Meningioma: a historical study of the tumor and its surgical management.

The history of meningioma is reviewed, highlighting the personalities and events that shaped our understanding and management of this tumor. Early descriptions, nomenclature, and the history of surgical removal of meningioma are discussed and the important role of this tumor in the development of neurosurgery as a whole is stressed.

History, 18th Century↗
PubMed1989

Human malignant astrocytoma xenografts migrate in rat brain: a model for central nervous system cancer research.

Fresh cells from two grade 3 human malignant astrocytomas were prelabeled with Phaseolus vulgaris leucoagglutin (PHAL) and then xenografted into freshly made implantation pockets in rat host cerebral cortex. Animals were sacrificed at 7, 14, 21 days, and 1 month postimplantation (DPI). Paraffin sections were double-labeled for the presence of glial fibrillary acidic protein (GFAP), a specific marker for astrocytes and differentiated astrocytoma cells, and PHAL, utilized as a marker for graft-derived cells. Grafted human astrocytoma cells were found on the glia limitans along the entire circumference of the brain, in the corpus callosum, internal capsule, entopeduncular nucleus, optic tract, and median eminence. In addition, astrocytoma cells were observed in the cingulum, habenula, arcuate, and supraoptic nucleus. Astrocytoma cells entered the spaces of Virchow-Robin, and migrated along parenchymal blood vessels and between the ependymal and subependymal layers of the third and lateral ventricles. The corpus callosum was a major migration route for the astrocytoma cells. The presence of basal lamina or parallel nerve fiber bundles was a common factor for these migration routes. The migration of the human astrocytoma xenografted cells in the rat brain followed the spread of human malignant astrocytomas in the human brain and is a valuable basic science tool in brain cancer research.

Animals↗
PubMed1989

Postoperative radiotherapy of supratentorial low-grade gliomas.

Forty-nine patients with supratentorial low-grade gliomas underwent surgery (biopsy or subtotal resection) and postoperative radiotherapy at the Mayo Clinic between 1976 and 1983. The median, 5-, and 10-year overall survivals for the total group were 6.5 years, 62%, and 14%, respectively. Nine prognostic variables were examined for their possible association with survival, including age, sex, site, size, CT enhancement, histologic type, extent of resection, radiation volume, and radiation dose. Of these variables, only histologic type was significantly associated with survival. The estimated 5-year survival was 100% for the 5 patients with pilocytic astrocytomas, 83% for the 20 patients with oligodendrogliomas or mixed oligo-astrocytomas, and 40% in the 24 patients with ordinary astrocytomas (log rank p = 0.001). Other possible prognostic variables, such as radiation volume or total dose, showed no association with survival. Twenty-seven patients had a documented treatment failure. For the 20 patients in whom the pattern of failure could be determined, all failed within their radiation portals. Eleven patients had additional tissue obtained following suspected disease recurrence. Tumor was found in ten of these patients, and radionecrosis in one.

Adolescent↗
PubMed1989

Short-term outcomes of skull fracture: a population-based study of survival and neurologic complications.

All Olmsted County, Minnesota, residents who experienced brain injury from 1935 through 1979 were identified and their medical records reviewed for survival and neurologic outcome. Minimum inclusion criteria included loss of consciousness or post-traumatic amnesia or neurologic evidence of brain injury or skull fracture. Of 4,660 cases identified, skull fractures were observed in 28%. Over half of brain-injured patients who died did so within 24 hours of trauma; among 1-day survivors, subsequent survival was moderately impaired, especially in older individuals. Mortality was lowest in subjects without a skull fracture and increased with fracture severity. Associated neurologic injuries, complications, and deficits were generally more common in patients with skull fracture than those without and were much more frequent with more severe skull fractures. The types of neurologic deficits differed little between those with and without fractures, except that subjects with complicated skull fractures had higher proportions of special sensory deficits and multiple deficits.

Adult↗
PubMed1989

Immunohistochemistry of human malignant astrocytoma cells xenografted to rat brain: apolipoprotein E.

Fresh xenografted human malignant astrocytoma cells migrate throughout the host rat brain. Cells from three Grade 3 human malignant astrocytomas were prelabeled with Phaseolus vulgaris leucoagglutinin (PHAL) and then xenografted into implantation pockets in rat host cerebral cortex. The human malignant astrocytoma cells in the host brain were immunocytochemically double-labeled for the presence of PHAL, which is used as a marker for graft derived cells, and either glial fibrillary acidic protein (GFAP), a specific marker for astrocytes and astrocytoma cells, or apolipoprotein E (APOE) 7 days, 14 days, 21 days, and 1 month later. Fresh human malignant astrocytoma cells (Grade 3 and 4) contained APOE and GFAP. The xenografted cells preserved APOE and GFAP in the host. PHAL double-labeled human malignant astrocytoma cells were found on the glia limitans along the entire circumference of the brain, in the corpus callosum, internal capsule, entopeduncular nucleus, optic tract, and median eminence. In addition, astrocytoma cells were observed in the cingulum, habenula, arcuate, and supraoptic nucleus. Astrocytoma cells entered the space of Virchow-Robin, migrated along parenchymal blood vessels and between the ependymal and subependymal layers of the third and lateral ventricles. APOE was a consistent marker for the migrating human malignant astrocytoma cells, but not an exclusive marker of the xenografted cells, since host rat reactive astrocytes also expressed APOE.

Animals↗