Biomedical subjects
M J Harrison
Publications and source records attributed to M J Harrison.
Radiation-induced meningiomas: experience at the Mount Sinai Hospital and review of the literature.
From the records of The Mount Sinai Hospital, seven cases which met established criteria for radiation-induced meningiomas were identified. This represents the largest series of radiogenic meningiomas documented in North America and includes both intracranial and intraspinal tumors. The records and pathological specimens were reviewed and these data analyzed with other cases retrieved from the world literature. This study reveals that radiation-induced meningiomas can be categorized into three groups based on the amount of radiation administered: 1) low dose; 2) moderate dose and miscellaneous; and 3) high dose. The overwhelming majority of cases had received low-dose irradiation (800 rad) to the scalp for tinea capitis and the second largest group resulted from high-dose irradiation for primary brain tumors (greater than 2000 rad). The unique features distinguishing radiation-induced meningiomas from other meningiomas are reviewed. Although histologically atypical tumors were common in this series, overt malignancy was not encountered. The preoperative management of these lesions should include angiography to evaluate for large-vessel occlusive vasculopathy, a known association of meningiomas induced by high-dose irradiation. Given the propensity these tumors possess for recurrence, a wide bony and dural margin is recommended at surgical resection.
Spinal instrumentation for degenerative disease of the lumbar spine.
Instrumentation for spinal implant is currently changing more rapidly than at any previous period in its 100-year history. At present, the most common indication for spinal instrumentation is degenerative disease of the lumbar spine, which can be roughly categorized as of three kinds: herniated lumbar disks, spondylolisthesis, and spinal stenosis. The literature on indications for arthrodesis is reviewed. A brief summary of the approach and type of instrumentation available for the lumbar spine is presented.
Sex difference in effect of aspirin on blood platelet aggregation may be artifact.
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Silent infarcts on computed tomography scans are more common in cardiogenic stroke.
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A comparison of parental interactions with term and preterm infants.
The purpose of this study was to compare father interactions to mother interactions with term and preterm infants. A purposive sample of 59 two-parent families with either a healthy term infant or a clinically normal preterm infant were recruited following the infant's birth. At 3 months, separate observations were made of each parent interacting with the infant during a teaching task in the home setting. As has been found in other research, mother-infant interactions scores were less favorable for preterm dyads. In contrast, father-infant interaction scores were less favorable for term dyads. The different pattern of interactions by the fathers was not explained by differences in paternal age, education, socioeconomic status, the father's current frequency of participation in child care or by infant gender.
Activation, structure, and organization of genes involved in microbial defense in plants.
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Prediction of infusion rates: computer study.
The administration of two test doses in the ratio 1:0.5 has been shown to provide sufficient data (time intervals) to predict the infusion rate necessary to maintain the concentration of a drug at the therapeutic threshold in a two-compartment pharmacokinetic model. If the relationship between the durations of action of the test doses is linear, only one test dose may be needed to predict the infusion rate.
Prediction of infusion rates: validation of a computer simulation using vecuronium.
In Phase 1 of the study a loading dose of vecuronium was given to 24 patients, followed by a sequence of infusions and boluses. The relationship between the duration of a bolus dose and the infusion rate necessary to maintain the required degree of neuromuscular block was demonstrated. In Phase 2 the data acquired from Phase 1 were used in an attempt to produce a predetermined degree of neuromuscular block. The aim was a block of neuromuscular function so that the height of the first twitch of a train-of-four was 15% of control. In the 10 patients studied the average height was 14.7% (SD 4.95%). It was concluded that it is possible to predict accurately the infusion dose of vecuronium required to achieve a predetermined degree of neuromuscular block, according to the duration of action of one or two test doses.
Intraoperative monitoring.
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The development of nursing diagnoses for aggregates and groups.
A focus on aggregates, groups, or communities as clients is an important characteristic of community health nursing practice. Community health nurse practitioners have identified population groups as one of five functional components in a typology of community health nursing practice. Questions have been raised, however, as to whether such groups need different forms of nursing diagnoses than those used for individuals. We attempted to use nursing diagnoses in a senior community health nursing course with undergraduate students that included experience working with aggregates or groups. Issues were identified in relation to the scope of the role of nurses in the community, the selection of the client, and the use of a taxonomy.
Persistent segmental cerebral artery constrictions in coital cephalgia.
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Rate of cerebral embolic events in relation to antibiotic and anticoagulant therapy in patients with bacterial endocarditis.
To quantitate embolic risk we studied a retrospective series of 61 patients with strictly defined bacterial endocarditis. Eighteen patients had neurological complications attributable to cerebral embolism. Seventeen embolic episodes occurred prior to antibiotic treatment and 8 episodes after its commencement. The rate of embolism per patient-week during a 20-week observation period showed a highly significant almost 4-fold reduction to a low level soon after antibiotics were started. Patients already on anticoagulation for prosthetic valves had the same embolic risk as those not so treated. The evidence suggests that anticoagulation at the time of diagnosis of bacterial endocarditis is not warranted.
Effect of induced hypertension on cerebral blood flow following middle cerebral occlusion in rats.
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Leptomyelolipoma: analysis of 20 cases.
Leptomyelolipoma (lumbosacral lipoma) is a common form of spinal dysraphism. The deficits produced include sensory, motor, bowel, and bladder dysfunction, and vary in incidence between the pediatric and adult populations. Twenty patients treated surgically at the Mount Sinai Hospital between 1972 and 1988 are reviewed. Fifty percent were 12 years of age or less and 50% were older than 18 years of age. The surgical approach was designed to accomplish untethering of the conus medullaris, debulking of the lipomatous mass compressing the cord, reconstruction of the dural canal, and reapproximation of the paraspinal muscles and lumbosacral fascia to prevent future trauma. Postoperatively, no patient experienced deterioration of neurological function. Of the symptomatic patients. 67% displayed dramatic improvement or became asymptomatic and 33% experienced stabilization of their deficits. The symptoms most resistant to surgical correction were orthopedic foot deformities and bowel dysfunction, whereas bladder dysfunction, motor weakness, and radiculopathies were most amenable to surgical therapy. Early surgical repair is recommended in these cases to forestall irreversible neurological damage.
Therapeutic touch.
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Detection of middle cerebral emboli during coronary artery bypass surgery using transcranial Doppler sonography.
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Role of platelets and antiplatelet agents in cerebrovascular disease. Clues from trials.
Significant reductions in mortality and in the incidence of nonfatal strokes have been shown in many trials of antiplatelet drugs, such as aspirin, in cerebrovascular disease. The limitations of these trials must be considered; however, if the trials are to provide useful information on the role of platelets in thrombotic processes. Difficulties arise because of the variable composition of emboli and the many possible causes of strokes. Some emboli are composed mainly of platelets while others consist of atheromatous material. Strokes may result from hemorrhage, hemodynamic disturbances, or lacunar infarction rather than thromboembolism. Nonetheless, the results of clinical trials suggest that at least some strokes can be prevented by antiplatelet drugs, thus implying that platelets are involved in the underlying disease process.