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Biomedical subjects

M S Edwards

Publications and source records attributed to M S Edwards.

At least 271 records · Page 15Linked to original sources
PubMed1983

Pediatric brain stem tumors: radiographic, pathological, and clinical correlations.

A retrospective analysis of the case histories of 21 pediatric patients (ages, 2.5 to 18 years) with a histologically proven diagnosis of brain stem glioma was performed to determine whether patterns of radiographic appearance could be correlated with pathology. Based on the computed tomographic or pneumoencephalographic appearance of the tumor at the time of clinical diagnosis, tumors were divided into four types: central intrinsic (Type I), central exophytic expansion into the 4th ventricle (Type II), eccentric exophytic expansion not involving the 4th ventricle (Type III), and both eccentric and central exophytic expansion (Type IV). Regardless of the radiographic classification, all patients except one, who harbored a well-differentiated astrocytoma in the area of the pons, had an anaplastic astrocytoma (n = 14) or a glioblastoma multiforme (n = 6). There was no appreciable difference in survival between patients with either tumor histology. The presence of a cystic component did not affect survival. High resolution computed tomographic scans, with reconstructed images of the posterior fossa, can predict the presence and location of brain stem tumors and associated cysts and probably the histological nature of the tumor.

Adolescent↗
PubMed1983

Computerized tomography of peripheral nerve lesions.

Nine patients with a peripheral nerve lesion (six intrinsic and three extrinsic) were evaluated with computerized tomography (CT). In all but one instance, the CT scans gave useful information regarding the anatomical location, size, and relationship of the lesion to surrounding structures. These cases illustrate the usefulness of CT as a diagnostic tool in the evaluation of peripheral nerve lesions.

Adult↗
PubMed1983

Primary cerebral neuroblastoma. Long-term follow-up review and therapeutic guidelines.

Primary cerebral neuroblastoma is a distinct pathological and clinical entity that differs from other primitive neuroectodermal tumors. To characterize the clinical course of this lesion, the authors performed a retrospective analysis in 11 patients who ranged in age from 17 months to 26 years. The tumor had no predilection for either sex. Signs and symptoms were mostly those associated with increased intracranial pressure. The lesions commonly involved the parietal and occipital lobes. Computerized tomography scans of nine patients showed five solid and four cystic lesions; calcifications were found more commonly in the solid lesions. Contrast enhancement was seen in all tumors, yet angiograms typically showed an avascular mass. Total removal of tumor was possible in only two patients, both with cystic tumors. The remaining nine underwent subtotal resection of a solid lesion (in five) or a cystic lesion (in four). All 11 patients underwent postoperative irradiation that included the spinal axis in two cases; only one received adjuvant chemotherapy (solid tumor). Four patients, all with solid tumors that initially were subtotally resected, had evidence of tumor recurrence. The only patient with a subtotally resected solid lesion who did not have recurrence received adjuvant chemotherapy. The six patients who had cystic lesions are free of recurrent tumor at 26 to 109 months after surgery. Based on follow-up analysis of the 11 patients, recommendations are proposed for the treatment of primary cerebral neuroblastomas.

Adolescent↗
PubMed1983

The laser in neurological surgery.

The use of lasers in neurosurgical procedures has received a great deal of attention recently. Surgical use of lasers has been viewed with suspicion and skepticism, probably because of (justified) apprehensions about the misuse of lasers in early work and about the ways in which laser light affects tissues, and a lack of understanding of the basic physics and practical operation of lasers. The authors review the physics, biophysics, experimental findings, and operative use of lasers in current neurosurgical practice, and discuss briefly their experience gained in over 150 neurosurgical procedures using the carbon dioxide and argon surgical lasers.

Arteriovenous Malformations↗
PubMed1982

Fetal treatment 1982.

Explore the source record for details and available documents.

Congenital Abnormalities↗
PubMed1982

Evaluation of misonidazole peripheral neurotoxicity in rats by analysis of nerve trains evoked response.

The clinical use of misonidazole and other nitroimidazole radiosensitizing agents is limited by the peripheral and central neurotoxicity that is produced in animals and humans. In a blinded study, rats treated with misonidazole at either 100 mg/kg or 300 mg/kg, 5 days/week for 3 weeks, were evaluated for peripheral neurotoxicity using nerve trains evoked responses. Only one rat treated at a dose of 100 mg/kg developed symptoms and signs of neurotoxicity, while all rats treated at 300 mg/kg developed these signs and symptoms. Nerve trains analysis made possible a diagnosis of neurotoxicity before overt clinical signs appeared. This test is non-invasive and may be useful for evaluating patients receiving nitroimidazole radiosensitizers as part of a radiation therapy regimen.

Animals↗
PubMed1982

Evaluation of Streptococcus pneumoniae type XIV opsonins by phagocytosis-associated chemiluminescence and a bactericidal assay.

The relative roles of serum factors required for opsonization of type XIV Streptococcus pneumoniae were investigated by means of luminol-enhanced chemiluminescence (CL), bactericidal, and immunofluorescence assays employing adult sera containing high (>1,000 ng of antibody nitrogen per ml) or low (<200 ng of antibody nitrogen per ml) antibody concentrations as determined by radioimmunoassay. Specific antibody concentration correlated directly with both total and heat-labile CL activity (P < 0.005) and with the bactericidal index (P < 0.05) at a serum concentration of 10%. The importance of specific antibody as an opsonin was confirmed by the abolition of CL activity and immunoglobulin immunofluorescence observed after absorption of heated sera with type XIV pneumococcal cells and by the dose response in CL and bactericidal activity observed with the addition of immunoglobulin G to hypogammaglobulinemic serum. A role for the classical complement pathway in opsonization was indicated by significantly greater CL integrals for high-antibody sera than for low-antibody sera depleted of factor D and by the bactericidal activity noted for untreated, but not magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid-chelated low-antibody sera. The alternative pathway contributed more than half of the CL activity of both high- and low-antibody sera. However, after magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid chelation, only sera with high antibody concentrations or agammaglobulinemic serum reconstituted with immunoglobulin G with high specific antibody levels supported significant bactericidal activity. Therefore, type-specific antibody and complement promote opsonization of type XIV S. pneumoniae, and this may occur via either complement pathway. These results suggest that CL is a suitable tool to delineate serum factors and their contribution to opsonization, but results must be related to other functional assays.

Antibodies, Bacterial↗
PubMed1982

Antibody-independent classical pathway-mediated opsonophagocytosis of type Ia, group B streptococcus.

The opsonophagocytic requirements of human sera containing endogenous complement for a variety of type Ia, and group B streptococcal strains were defined. Significant reduction (>==90%) in colony-forming units was noted after a 40-min incubation for the highly encapsulated, mouse-passed prototype strain 090 by sera containing moderate to high concentrations of antibody to type Ia polysaccharide (mean, 16.5 mug/ml), whereas bacterial growth occurred in 25 sera with low levels of specific antibody (mean, 2.1 mug/ml). This absolute requirement for a critical amount of specific antibody in promoting opsonophagocytic killing of strain 090 was not found when 18 fresh clinical type Ia isolates were tested. In antibody-deficient and agammaglobulinemic sera, respectively, mean reductions in colony-forming units of 94 and 95% were seen for fresh clinical isolates, whereas strain 090 was not killed by polymorphonuclear leukocytes in the presence of these sera. All strains required a considerable amount of specific antibody for alternative pathway-mediated opsonophagocytosis. That opsonophagocytic killing of clinical type Ia isolates was mediated by the classical pathway in a nonantibody-dependent fashion was shown when MgEGTA chelation of agammaglobulinemic serum or use of serum deficient in C2 resulted in bacterial growth. The addition of C2 to C2-deficient serum restored bactericidal activity of this serum. These experiments indicate that substances other than the exposed surface of the type Ia capsular polysaccharide initiate classical pathway-mediated opsonophagocytosis of clinical isolates of type Ia, group B streptococci by human sera in the absence of immunoglobulin. Perhaps, a deficiency in classical complement pathway function is critical to the susceptibility of neonates to type Ia, group B streptococcal disease.

Animals↗
PubMed1982

Prophylaxis of thromboembolism in the neurosurgical patient: a review.

The incidence of postoperative thromboembolic complications in neurosurgical patients is 29 to 43%. However, anticoagulant treatment of these complications increases the inherent risk of hemorrhage into the operative site. We have reviewed the literature on the prophylaxis of deep vein thrombosis and pulmonary embolism; the incidence of thromboembolic complications, the mechanism of deep venous thrombosis, risk factors, and methods of prophylaxis for deep vein thrombosis are discussed in relation to possible prophylactic treatment of neurosurgical patients. We conclude from our review that low dose heparin therapy is indicated for patients undergoing elective neurosurgical procedures, especially for patients over the age of 40 and for patients under the age of 40 who are known to be at risk of developing thromboembolic complications.

Anticoagulants↗
PubMed1982

Hypoglossal neurilemmoma: case report and review of the literature.

The case of a patient harboring a rare intracranial hypoglossal nerve sheath tumor is presented, and the literature concerning this lesion, especially with relation to age and sex patterns and the initial and presenting symptoms and signs, is reviewed. The importance of a thorough radiological examination with detailed vertebral angiography and contrast-enhanced computed tomographic scans of the hypoglossal canal is discussed. Based on our experience with this patient, we recommend total excision of this lesion.

Adolescent↗
PubMed1982

Comparison of the brain tissue response in rats to injury by argon and carbon dioxide lasers.

This study compares the acute and chronic response of brain tissue to injury by equal power density, focused argon (Ar) and carbon dioxide (CO2) laser beams. A cortical incision from 0.2-second laser pulses of 12.5 X 10(3) W/cm2 power density was made in the exposed cortex of 32 rats using either the CO2 or the Ar laser. The brains were examined at intervals from 1/2 hour to 1 month after injury. Histologically, all brain incisions were sharply demarcated hemispheroidal defects with a vaporized center bordered by a zone of coagulation necrosis surrounded by edema. The laser incisions were found to be of equal depth (less than 1 mm). The average cortical surface diameter of the CO2 laser incision was 0.86 mm for a focused beam spot size 0.45 mm in diameter, compared with 0.65 mm with the Ar laser, which had a focused beam spot size 0.15 mm in diameter. In both incisions, some delayed depth effect was observed. A progression of the tissue necrosis by approximately 17% was observed during the first 24 hours after injury. During the first 4 hours after injury, the Evans blue blood-brain barrier defect (EBBD) surrounding the cortical incisions averaged 5.80 mm2 for the CO2 incision and 0.888 mm2 for the Ar incision. In both types of brain incision, the EBBD appeared to resolve by 24 hours after injury. At 1 month after injury, a core of coagulation necrosis surrounded by mild fibrillary gliosis was observed. At the power density and focused beam spot sizes used, there was no significant difference in the overall brain tissue response to Ar and CO2 laser lesions.

Animals↗
PubMed1982

Spinal cord pathways mediating somatosensory evoked potentials.

Using a CO2 laser, discrete thoracic spinal cord lesions were made in cats anesthetized with ketamine and xylazine (Rompun). Differences in cortical somatosensory evoked potentials (SEP's) produced with high-intensity stimulation (20 times the motor threshold) of each posterior tibial nerve determined for nine different combinations of unilateral spinal cord lesions. The results of these studies show that nerve fibers in the ipsilateral dorsal column, the ipsilateral dorsal spinocerebellar tract, and the contralateral ventrolateral tracts with respect to the side of leg stimulation, contribute to cortical SEP's. A lesion of the dorsal spinocerebellar tract affected only the early waves (less than 30 msec) of the SEP from leg stimulation ipsilateral to the side of the lesion, whereas a solitary lesion of the ventrolateral tract caused changes primarily in the amplitude of later waves (greater than 30 msec) of the SEP produced by contralateral leg stimulation. Lesions involving one-half of the dorsal column caused changes in the amplitude of both the early and late waves produced by stimulation ipsilateral to the side of the lesion. The effects of various combinations of lesions on the cortical SEP's were not additive, which indicates significant interaction between afferent pathways. These findings suggest that high-intensity peripheral nerve stimulation, which activates both C and A fibers, could be used intraoperatively to assess spinal cord function with more accuracy than the current practice of using a stimulus strength of twice the motor threshold. The importance of using anesthetic agents that do not depress cortical activity (which may affect the later components of the SEP) is also emphasized.

Animals↗
PubMed1982

Psychiatric day programs: a descriptive analysis.

Partial hospitalization programs evolved as a result of a variety of financial, social and therapeutic circumstances. At present, these programs can take one of several different forms. Of these, the most common ones are the three day programs--day hospital, day treatment, and day care. In theory, each of the three would serve a distinct population, have a clearly defined structure, and be administered in a predictable manner. This article contrasts theory with practice and makes an analysis of the actual and potential effectiveness such as demographics and economics are presented. Recommendations for the present and future follow from projected long range shifts and trends.

Community Mental Health Services↗
PubMed1982

Subdural empyema: an unusual complication of meningococcal meningitis.

Subdural empyema rarely is associated with bacterial meningitis in infants, particularly when the etiologic agent is Neisseria meningitidis. We have described a 3-month-old infant in whom relapse of meningitis due to Meningococcus group C was accompanied by a right-sided subdural empyema. Full recovery followed appropriate antimicrobial therapy and closed drainage.

Brain Abscess↗
PubMed1981

CSF polyamines: a new and important means of monitoring patients with medulloblastoma.

An earlier study that showed the importance of cerebrospinal fluid polyamine levels for monitoring patients harboring medulloblastomas was expanded to 210 determinations evaluated in 32 patients. The results and conclusions of our earlier study have been confirmed in this expanded patient group. Patient status, with regard to either progression or regression of tumor, was determined by correlating polyamine levels with neurologic examination, computerized tomography, radionuclide scan, cerebrospinal fluid cytology, and myelography. The polyamine assay was predictive of recurrence in 15 patients; three false negatives and no false positives were found. We feel that cerebrospinal fluid polyamine determinations should be a routine diagnostic procedure in the long-term monitoring of patients harboring medulloblastoma.

Chromatography, Ion Exchange↗