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Biomedical subjects

D G Norris

Publications and source records attributed to D G Norris.

65 records · Page 4Linked to original sources
PubMed1981

Focal encephalopathy following methotrexate therapy. Administration via a misplaced intraventricular catheter.

Two patients with lymphoreticular malignant neoplasms and leptomeningeal tumor spread were treated with intraventricular administration of methotrexate via an Ommaya reservoir. The intraventricular instillation of methotrexate resulted in focal CNS damage in brain parenchyma inadvertently pierced by the shunt. Disorientation, aphasia, and right hemiparesis developed in both patients. Computed tomography disclosed a contrast-enhancing, low-density mass in the left cerebral cortex where the distal shunt tip was lodged. In one case the lesion was pathologically consistent with chronic inflammation. A lesion occurred in one patient despite repositioning of the shunt prior to methotrexate instillation. Shunt removal and administration of systemic corticosteroids resulted in resolution of symptoms in one patient.

Adolescent↗
PubMed1981

Improved relapse-free survival in medulloblastoma utilizing modern techniques.

Between 1969 and 1979, 22 patients with medulloblastoma were treated by the same surgical group and radiation therapy group. The patients were divided into two groups because of the clinical availability in December 1974 of the computed tomographic (CT) scanner and of the operating microscope used in the initial surgical procedure. There were 11 patients in each group. The percentage of patients with a relapse-free survival in the group treated between 1969 and 1974 (Group 1) was 38% at 4 years. The survival in the 11 patients treated between 1974 and 1979 (Group 2) was 84% at 4 years. This improvement is statistically significant (P less than or equal to 0.001). All patients received the same dose of radiation. Efforts to minimize the tumor burden by total surgical resection did not increase postoperative morbidity or mortality. These results are discussed, along with the relative impact of the CT scan, total resection at operation, and increased focus for radiation therapy on the improved outcome.

Cerebellar Neoplasms↗
PubMed1980

Desquamative interstitial pneumonitis in children.

Interstitial pneumonitis in children is a rare and poorly understood disease. Controversy exists as to whether the varoius histologic changes encountered represent different disease or a spectrum of the same disease. Fourteen biopsy-confirmed cases of desquamative interstitial pneumonitis in children were seen at the Mayo Clinic between 1953 and 1975. A search of the literature revealed 14 additional cases but no series of exclusively desquamative interstitial pneumonitis. The most frequent symptoms were retardation of growth and dyspnea, often accompanied by cough. Tachypnea was the most common finding on examination; rales, cyanosis, and clubbing were variably present. The chest roentgenogram was distinctly abnormal in all cases; it usually revealed a combined interstitial and alveolar pattern extending bilaterally from the hilus to the base. Results of laboratory studies were nonspecific for desquamative interstitial pneumonitis. All 28 patients in this review were treated with corticosteroids; 17 (61 percent) survived. Desquamative interstitial pneumonitis was found in association with a variety of other major illnesses. The cause remains unknown.

Adolescent↗
PubMed1977

Systemic lupus erythematosus in children: the complex problems of diagnosis and treatment encountered in 101 such patients at the Mayo Clinic.

Between 1945 and 1970, 101 children (86 girls and 15 boys) with systemic lupus erythematosus were evaluated at the Mayo Clinic. Only 9 children were less than 9 years old at the time of diagnosis. The most frequent presenting complaint was arthralgia; fever, fatigue, and a "butterfly" malar rash also were common. Renal involvement, found in more than 76 per cent of patients, was a prognostically poor sign. The overall survival of children with renal involvement is improved by the use of adequate steroid therapy.

Adolescent↗
PubMed1975

Hodgkin's disease in childhood.

A retrospective study of 116 children with Hodgkin's disease diagnosed in the period 1935-1970 was undertaken to assess the prognostic role of histopathologic classiciation and clinical extent of the disease. The ages of the 80 boys and 36 girls ranged from 2.5 years to 15.0 years (mean, 10.0 years). The histopathologic diagnosis by lymph node biopsy revealed lymphocyte predominance in 22, nodular sclerosis in 67, mixed cellularity in 24, and lymphocyte depletion in 3. Within the subgroup of nodular sclerosis, 47 biopsies had classic well-developed collagenous bands, whereas 20 were in the cellular phase (10 without collagenous bands and 10 with minimal collagen). The clinical extent of disease was determined. There were 33 patients with Stage I disease, 38 with Stage IIA, 12 with Stage IIB, 24 with Stage III, and 9 with Stage IV. Survival correlated with histopathologic type and clinical stage, but not with age or sex. Survival was not dependent on the degree of collagenization in nodular sclerosis. There were 28 patients who survived for more than 10 years. Four of these 29 subsequently died owing to acute myelomonocytic leukemia, carcinoma of the breast, sepsis, and progression of Hodgkin's disease, respectively. Neoplasms developed in two other long-term survivors (thyroid carcinoma in one, and multiple basal cell carcinomas in the other).

Adolescent↗
PubMedDate not supplied

Indications, outcomes, and provider volumes for carotid endarterectomy.

CONTEXT: While trials have demonstrated that carotid endarterectomy is superior to best medical therapy, most recently among asymptomatic patients, uses and outcomes of the procedure in more representative settings have not been established. OBJECTIVES: To profile the use and outcomes of carotid endarterectomy in a representative sample of Ohio's Medicare beneficiaries and to examine the relationships between provider-specific procedural volumes and patient outcomes. DESIGN: Retrospective cohort using Medicare Provider Analysis and Review files supplemented by detailed reviews of medical records on a random sample of patients. SETTING: Ohio hospitals performing carotid endarterectomy. PATIENTS: A random sample of 678 charts of the 4120 non-health maintenance organization Medicare beneficiaries who underwent carotid endarterectomy between July 1, 1993, and June 30, 1994. MAIN OUTCOME MEASURES: Nonfatal stroke or death within 30 days of surgery. RESULTS: The reviewed patients were similar to all eligible patients in sociodemographic characteristics and 30-day mortality rates. Among the 678 patients, indications for surgery were asymptomatic carotid stenosis in 167 (24.6%), transient ischemic attack in 294 (43.4%), completed stroke in 62 (9.1%), and nonspecific symptoms in 155 (22.9%). Thirty-two patients (4.7%) died or suffered nonfatal strokes by 30 days postoperatively. In univariate analyses, rates varied by hospital volume (P=.004) but not surgeons' volume (P=.47), although power to detect this difference was limited. Patients at higher- and lower-volume hospitals had similar indications and distributions of comorbidities. In analyses controlling for indications, comorbid conditions, and surgeon's volume, being operated on in a higher-volume hospital conferred a 71% reduction in risk for 30-day stroke or death (odds ratio, 0.29; 95% confidence interval, 0.12-0.69; P=.006). CONCLUSIONS: Almost half (47.5%) of the carotid endarterectomies among Ohio's Medicare population are performed on persons who are asymptomatic or who have nonspecific symptoms. These results highlight the importance of identifying patients and providers having the most favorable outcome profiles. The higher rate of adverse outcomes observed in lower-volume hospitals deserves further investigation, as it does not appear to be due to differences in patient selection.

Aged↗
PubMedDate not supplied

Interpretation of DW-NMR data: dependence on experimental conditions.

This review examines the effect of experimental conditions on the data obtainable from diffusion weighted NMR experiments. The origin and forms of the Stejskal-Tanner experiment are presented, and the relative merits of bipolar to monopolar diffusion weighting gradient pulses are discussed, as are those of spin-echo and stimulated-echo weighting schemes. The short pulse Stejskal-Tanner experiment as required for q-space imaging is described. Criteria for successful diffusion weighted imaging are given, and current strategies for diffusion weighted imaging are evaluated against these. The range of biological objects accessible to diffusion weighted NMR is summarized, together with the associated experimental limitations. In the final section the dependence of diffusion weighted NMR data on diffusion time and b-value range is examined, and the relationship between apparent restricted diffusion and the size of the extracellular space is demonstrated.

Diffusion↗