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E Alexander

Publications and source records attributed to E Alexander.

At least 55 records · Page 3Linked to original sources
PubMed1997

Prostate pathology case study seminar.

Great strides have been made in the past decade in our understanding of the pathology of the prostate. Diagnostic criteria have been proposed, debated, and refined for a number of entities, including prostatic intraepithelial neoplasia, atypical adenomatous hyperplasia, basal cell proliferations, postatrophic hyperplasia, verumontanum mucosal gland hyperplasia, and numerous new variants of prostatic adenocarcinoma such as ductal adenocarcinoma, mucinous carcinoma, signet ring cell carcinoma, and lymphoepithelioma-like carcinoma. This report presents a series of case studies in prostate pathology which illustrate some of the contemporary issues which confront the pathologist and urologist.

Adenocarcinoma↗
PubMed1997

Permanent low-activity iodine-125 implants for cerebral metastases.

Beginning in 1987, selected patients with metastatic brain tumors were treated with permanent implants of low-activity radioactive iodine-125(125I) seeds. These patients underwent craniotomy, gross total resection of the metastatic lesion, and placement of the seeds. In general, criteria for treatment included the presence of a recurrent tumor with a volume too large to permit radiosurgery, and a Karnofsky Performance Score of 70 or higher. Thirteen patients underwent 14 implant procedures; all received external whole-brain radiotherapy. Implant dose ranged from 43 Gy to 132 Gy, with a mean of 83 Gy. Survival after implantation ranged from 2 weeks to almost 9 years, with a median of 9 months. Clinical and radiographic local control was obtained in 9 patients. Two patients died of acute, postoperative complications within a month of implantation, so no information regarding tumor control is available for them. Late complications included a bone flap infection in one patient and a CSF leak in another; both were treated without further sequelae. These results demonstrate that permanent 125I implants can results in good survival and quality of life, and occasionally can yield long-term survival. Potentially, it is a cost-effective treatment in that a separate procedure for stereotactic implantation or radiosurgery is not needed, as is the case with the use of temporary high-activity seeds. The permanent implantation itself adds less than 10 minutes to the craniotomy, and the risk of symptomatic radiation necrosis is low. We recommend consideration of this procedure in patients harboring large, recurrent metastatic tumors that require further surgery.

Adult↗
PubMed1997

Development and implementation of intraoperative magnetic resonance imaging and its neurosurgical applications.

OBJECTIVE: We describe the development and implementation of a new open configuration magnetic resonance imaging (MRI) system, with which neurosurgical procedures can be performed using image guidance. Our initial neurosurgical experience consists of 140 cases, including 63 stereotactic biopsies, 16 cyst drainages, 55 craniotomies, 3 thermal ablations, and 3 laminectomies. The surgical advantages derived from this new modality are presented. METHODS: The 0.5-T intraoperative MRI system (SIGNA SP, Boston, MA), developed by General Electric Medical Systems in collaboration with the Brigham and Women's Hospital, has a vertical gap within its magnet, providing the physical space for surgery. Images are viewed on monitors located within this gap and can also be acquired in conjunction with optical tracking of surgical instruments, establishing accurate intraoperative correlations between instrument position and anatomic structures. RESULTS: A wide range of standard neurosurgical procedures can be performed using intraoperative MRI. The images obtained are clear and provide accurate and immediate information to use in the planning and assessment of the progress of the surgery. CONCLUSION: Intraoperative MRI allows lesions to be precisely localized and targeted, and the progress of a procedure can be immediately evaluated. The constantly updated images help to eliminate errors that can arise during frame-based and frameless stereotactic surgery when anatomic structures alter their position because of shifting or displacement of brain parenchyma but are correlated with images obtained preoperatively. Intraoperative MRI is particularly helpful in determining tumor margins, optimizing surgical approaches, achieving complete resection of intracerebral lesions, and monitoring potential intraoperative complications.

Biopsy↗
PubMed1997

The present and future role of intraoperative MRI in neurosurgical procedures.

OBJECTIVE: We have worked in conjunction with scientists from the General Electric Corporation over 6 years to develop an open-bore MR imaging system (0.5 T) enabling optimal vertical access of surgeon and assistant to the patient, and real-time imaging during major neurosurgical procedures. METHODS: The intraoperative MR system (MRT) is located in a specially modified operative suite that combines the features of an MR-imaging suite with a fully functional operating room. An MR-compatible anesthesia machine and patient-monitoring device are located next to the magnet. The position of instruments, platforms and supports may be mapped in the operative field using 3 charge-coupled device video cameras mounted in the overhead support truncheon that follow various light-emitting diodes on the devices (Pixsys). The MR image plane can be defined as the axial, coronal or sagittal views through a point along the vector beneath the Pixsys tripod. A variety of surface coils were designed to take full advantage of full open patient access. The software, implemented by a technologist located outside the MR room, is now equivalent to that available on the commercial 0.5-tesla Signa Advantage system. Development of very robust 3-dimensional software in conjunction with the Surgical Planning Laboratory (SPL) at the Brigham & Women's Hospital is the subject of significant effort. The MRT system has been shown to possess imaging capabilities comparable, or even slightly superior (by 10%), to a conventional 0.5-tesla MR scanner. Two modified liquid-crystal display screens are mounted on the magnet housing for the surgeon to monitor the images during the procedures. Projection into larger screens or the operating microscope is under development. RESULTS: We have performed 110 neurosurgical cases in MRT as of January 29, 1997, including 47 biopsies, 6 catheter placements, 4 cyst drainages, 47 craniotomies for resection, 3 spinal cases (1 syrinx drainage), and 3 laser tumor ablations. CONCLUSIONS: MRT is especially useful in guiding biopsies and resections near cysts, ventricles and critical vascular structures where preoperative images with framed/frameless techniques would be inadequate to show anatomic changes during the procedure. Real-time images of a biopsy needle within the abnormal area are very useful in cases of subtle pathologic change. More complete resection of infiltrative tumor is readily accomplished. SPL image fusion of SPECT and neurofunctional data (e.g. from magnetic stimulation preoperatively) into the imaging space enables the surgeon to better visualize tumor invasion or neural function in real-time imaging during resection. Imaging of thermal gradients for cryoprobe or laser ablation, and combination with endoscopy and robotics will offer additional benefit in the performance of difficult neurosurgical procedures.

Biopsy↗
PubMed1997

rhIGF-I administration reduces insulin requirements, decreases growth hormone secretion, and improves the lipid profile in adults with IDDM.

IDDM is associated with elevated circulating levels of growth hormone (GH) and reduced insulin-like growth factor I (IGF-I). GH antagonizes the action of insulin-increasing insulin requirements in IDDM. The effects of subcutaneously administered rhIGF-I on glycemic control, insulin requirements, and GH secretion were studied in eight adults with IDDM. Patients received either placebo or rhIGF-I (50 microg/kg b.i.d.) for 19 days in a randomized, double-blind, parallel-design, placebo-controlled trial. Overnight GH, plasma glucose, free insulin, IGF-I, fructosamine, and lipid profiles were assessed during this period. rhIGF-I therapy increased IGF-I concentration from 117.1 +/- 14.2 (mean +/- SE) ng/ml (baseline) to 310.5 +/- 40.6 and 257.1 +/- 41.2 ng/ml on day 5 (P < 0.01 vs. baseline) and day 20 (P < 0.01 vs. baseline), respectively. After 19 days of rhIGF-I treatment, fructosamine concentrations were unchanged compared with baseline (439 +/- 32 vs. 429 +/- 35 micromol/l, day -1 vs. day 20, respectively), yet insulin requirements were decreased by approximately 45% (0.67 +/- 0.08 vs. 0.36 +/- 0.07 U x kg(-1) x day(-1), day -1 vs. day 19, respectively, P < 0.005). After 4 days of rhIGF-I therapy, there was a decrease in free insulin levels (8.38 +/- 1.47 vs. 4.98 +/- 0.84 mU/l, P < 0.05), mean overnight GH concentration (12.6 +/- 3.3 vs. 3.8 +/- 2.1 mU/l, P = 0.05), and total cholesterol and triglycerides (4.68 +/- 0.31 vs. 4.25 +/- 0.35 mmol/l, P < 0.05, 1.27 +/- 0.19 vs. 0.95 +/- 0.21 mmol/l, P < 0.001, respectively). There was no change in any variable in the placebo-treated patients. This study demonstrates that subcutaneous administration of rhIGF-I decreases insulin requirements and improves the plasma lipid profile while maintaining glycemic control in adults with IDDM. The excess nocturnal release of GH, characteristic of IDDM, is also decreased by rhIGF-I therapy.

Adult↗
PubMed1996

Fractionated stereotactic radiotherapy for the treatment of acoustic neuromas: preliminary results.

PURPOSE: To evaluate the efficacy and toxicity of fractionated, stereotactic radiotherapy (SRT) for acoustic neuromas. METHODS AND MATERIALS: Twelve patients with acoustic neuroma were treated with SRT between June 1992 and October 1994. Follow-up ranged from 16-44 months. Patient age ranged from 27-70 (median: 45). Eight patients were treated with primary SRT and four patients were treated after primary surgical intervention for recurrent [3] or persistent [1] disease. Tumor volumes were 1.2-18.4 cm3 (median: 10.1 cm3). Collimator sizes ranged from 30-50 mm (median: 37.5). Tumors received 1.8 Gy/day normalized to the 95% isodose line. Patients received a minimum prescribed dose of 54 Gy in 27-30 fractions over a 6-week period. RESULTS: After a median follow-up of 26.5 months, local control was obtained in 12 out of 12 lesions. Tumor regression was noted in three patients, and tumor stabilization was found in the remaining nine patients. No patient developed a new cranial nerve deficit. One patients developed worsening of preexisting Vth cranial neuropathy and another experienced a decrease in hearing. However, all nine patients with useful hearing prior to SRT maintained useful hearing at last follow-up. CONCLUSIONS: Stereotactic radiotherapy provided excellent local control without new cranial nerve deficits. These results must be viewed as tentative in nature because of the small number of patients and the short median follow-up period.

Adult↗
PubMed1996

Cardioactive compounds from Eremophila species.

The isolation and identification of two cardioactive compounds from two Eremophila species (Myoporaceae) considered important in the pharmacopoeia of the Australian Aboriginal people is described. Verbascoside, isolated from the methanol and water extracts of E. alternifolia leaves, mediated significant increases in chronotropism, inotropism and coronary perfusion rate (CPR) in the Langendorff rat heart. Geniposidic acid, isolated from the methanol extract of E. longifolia leaves, mediated an inhibitory effect with significant negative chronotropism, negative inotropism and CPR.

Animals↗
PubMed1996

Radiosurgery for hemangioblastoma: results of a multiinstitutional experience.

PURPOSE: Between June 1988 and June 1994. 38 hemangioblastomas were treated with stereotactic radiosurgery (SR) at three SR centers to evaluate the efficacy and potential toxicity of this therapeutic modality as an adjuvant or alternative treatment to surgical resection. METHODS AND MATERIALS: SR was performed using either a 201-cobalt source unit or a dedicated SR linear accelerator. Of the 18 primary tumors treated, 16 had no prior history of surgical resection and were treated definitively with SR and two primary lesions were subtotally resected and subsequently treated with SR. Twenty lesions were treated with SR after prior surgical failure (17 tumors) or failure after prior surgery and conventional radiotherapy (three tumors). Eight patients were treated with SR for multifocal disease (total, 24 known tumors). SR tumor volumes measured 0.05 to 12 cc (median: 0.97 cc). Minimum tumor doses ranged from 12 to 20 Gy (median: 15.5 Gy). RESULTS: Median follow-up from the time of SR was 24.5 months (range: 6-77 months). The 2-year actuarial over-all survival was 88 +/- 15% (95% confidence interval). Two-year actuarial freedom from progression was 86 +/- 12% (95% confidence interval). The median tumor volume of the lesions that failed to be controlled by SR was 7.85 cc (range: 3.20-10.53 cc) compared to 0.67 cc (range: 0.05-12 cc) for controlled lesions (p - 0.0023). The lesions that failed to be controlled by SR received a median minimum tumor dose of 14 Gy (range: 13-17 Gy) compared to 16 Gy (range: 12-20 Gy) for controlled lesions (p = 0.0239). Seventy-eight percent of the surviving patients remained neurologically stable or clinically improved. There were no significant permanent complications directly attributable to SR. CONCLUSIONS: This report documents the largest experience in the literature of the use of SR in the treatment of hemangioblastoma. We conclude that SR: (a) controls the majority of primary and recurrent hemangioblastomas; (b) offers the ability to treat multiple lesions in a single treatment session, which is particularly important for patients with Von Hippel-Lindau Syndrome; and that (c) better control rates are associated with higher doses and smaller tumor volumes.

Adrenal Cortex Hormones↗
PubMed1996

A multiinstitutional outcome and prognostic factor analysis of radiosurgery for resectable single brain metastasis.

PURPOSE: Recent randomized trials of selected patients with single brain metastasis comparing resection followed by whole-brain radiotherapy (WBRT) to WBRT alone have shown a statistically significant survival advantage for surgery and WBRT. A multiinstitutional retrospective study was performed, which identified comparable patients who were treated with stereotactic radiosurgery (RS) and WBRT. METHODS AND MATERIALS: The RS databases of four institutions were reviewed to identify patients who met the following criteria: single-brain metastasis; no prior cranial surgery or WBRT; age > 18 years; surgically resectable lesion; Karnofsky Performance Status (KPS) > or = 70 at time of RS; nonradiosensitive histology. One hundred twenty-two patients were identified who met these criteria. Patients were categorized by: (a) status of the primary, (b) status of non-CNS metastasis, (c) age, (d) baseline KPS (from 70-100), (e) histology, (f) time from diagnosis of primary to the detection of the brain metastasis, (g) gender, and (h) tumor volume. RS was performed with a linear accelerator based technique (peripheral dose range was 10-27 Gy, median was 17 Gy). WBRT was performed in all but five patients who refused WBRT (dose range was 25-40 Gy, median was 37.5 Gy). RESULTS: The median follow-up for all patients was 123 weeks. The overall local control rate (defined as lack of progression in the RS volume) was 86%. Intracranial recurrence outside of the RS volume was seen in 27 patients (22%). The actuarial median survival from date of RS is 56 weeks, and the 1-year and 2-year actuarial survival rates are 53% and 30%. The median duration of functional independence (sustained KPS > or = 70) is 44 weeks. Nineteen of 77 deaths were attributed to CNS progression (25% of all deaths). Multivariate analysis revealed the following factors to be statistically significant predictors of survival: baseline KPS (p < .0001) and absence of other sites of metastasis (p = 0.008). CONCLUSION: The RS in conjunction with WBRT for single brain metastasis can produce substantial functional survival, especially in patients with good performance status and without extracranial metastasis. These results are comparable to recent randomized trials of resection and WBRT. The advantages of RS over surgery in terms of cost, hospitalization, morbidity, and wider applicability strongly suggest that a randomized trial to compare RS with surgery is warranted.

Adult↗
PubMed1996

Epidemiology of EBV and Hodgkin's lymphoma.

The incidence of Hodgkin's disease shows marked heterogeneity with respect to age, gender, race, geographical locale, social class and histological subtype. The Epstein-Barr virus (EBV) is associated with a proportion of cases, approximately 40% in developed countries, and there is a body of evidence which suggests that mixed cellularity Hodgkin's disease is more likely to be EBV-associated than nodular sclerosis Hodgkin's disease. This study investigates the relationship between EBV and both age and histological subtype. We confirm the above subtype distribution and that childhood and older adult cases are more likely to be EBV-associated than young adult cases. Young adult nodular sclerosis cases are rarely EBV-associated providing further evidence that this is a separate disease entity. The results of this study support the multiple aetiology hypothesis which suggests that Hodgkin's disease in different age groups has different aetiologies. The epidemiology of Hodgkin's disease and studies investigating the distribution of EBV-associated cases are reviewed.

Adolescent↗