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Biomedical subjects

J R Anderson

Publications and source records attributed to J R Anderson.

At least 199 records · Page 11Linked to original sources
PubMed1994

Combination trial of subcutaneous recombinant alpha 2 b interferon and oral cyclophosphamide in follicular low-grade non-Hodgkin's lymphoma.

The follicular non-Hodgkin's lymphomas (NHL) have been among those tumors demonstrated to show frequent responses to alpha interferon in phase I and II clinical trials. In addition, there are data suggesting that alpha interferon demonstrates synergistic antitumor activity with alkylating agents in animal models for a number of tumors. Based on these data, Cancer and Leukemia Group B (CALGB) undertook a phase II pilot study of the combination of interferon rIFN alpha 2b (2 x 10(6) IU/m2 s.c. tiw) and cyclophosphamide (100 mg/m2 per day orally) with the ultimate purpose of examining this combination as long-term therapy of follicular lymphoma in comparison to oral cyclophosphamide alone. One hundred five advanced stage III or IV eligible patients with pathologically diagnosed International Working Formulation B or C histology were entered on CALGB 8553 to determine toxicity and response rates to the combination. Both previously chemotherapy-treated patients (32) and patients without prior chemotherapy (73) were entered on study. For patients without prior chemotherapy the overall response rate to the combination regimen was 86% with 58% of chemotherapy-treated patients achieving complete response. Chemotherapy-treated patients had a total response rate of 62% with only 25% complete responders. Complete responses in patients without prior chemotherapy were positively correlated with absence of B symptoms, and good performance status and negatively correlated with the histological subtype of follicular mixed small-cleaved and large cell histology (IWF C); only performance status was significantly correlated with response in patients who had previously had chemotherapy. Survival at 5 years is estimated to be 63% for those without chemotherapy and 39% for those previously treated with chemotherapy patients. The maximum toxicities experienced during therapy with the combination regimen of cyclophosphamide and interferon alpha were primarily related to myelosuppression. Sixty-seven percent of patients without prior chemotherapy and 65% of patients receiving prior chemotherapy experienced severe leukopenia while severe thrombocytopenia and anemia occurred in 6-31% of these patients. Non-myelosuppressive toxicities were less frequently seen. These response rates are similar to those achieved in a previous CALGB trial with oral cyclophosphamide as a single agent, although severe myelotoxicity was increased to approximately 60% of patients from less than 10% with the single-agent therapy. The combination of alpha interferon and cyclophosphamide administered in this fashion is safe when peripheral counts are carefully monitored. Randomized studies of this regimen in comparison to oral cyclophosphamide are currently in progress.

Administration, Oral↗
PubMed1994

Disseminated nonlymphoblastic lymphoma of childhood: a Childrens Cancer Group study, CCG-552.

PURPOSE: To assess the efficacy of a chemotherapy-only regimen in pediatric patients with disseminated non-lymphoblastic lymphoma and acute B-cell leukemia (B-ALL). PATIENTS AND METHODS: Sixty-eight eligible patients with previously untreated disseminated non-lymphoblastic lymphoma were enrolled on a Childrens Cancer Group study. Therapy included cycles of chemotherapy, systemic and intrathecal (IT), ever 3 weeks for a total maximal duration of 57 weeks. Fifty-five patients had small non-cleaved cell lymphoma (SNCCL) and 13 had diffuse large cell lymphoma (DLCL). Forty-seven were stage III, six were stage IV, and 15 had B-ALL; 13 had central nervous system (CNS) involvement. RESULTS: Four year event-free survival (EFS) was 53% (SE +/- 12%). Stage III SNCCL patients with LDH < 500 IU/L achieved an improved EFS compared to other SNCCL patients (86% vs. 42% 4 year EFS, P = .072). The primary site of failure for advanced stage SNCCL patients was the CNS. All Ki-1-positive DLCL patients relapsed. Patterns of failure, time to relapse, and outcome following relapse differed between SNCCL and DLCL patients. CONCLUSIONS: Advanced stage SNCCL requires better CNS-directed chemotherapy to reduce the CNS failure rate; however, the achievement of durable disease-free survival in four of 11 patients with CNS disease without use of cranial irradiation suggests merit for further evaluation of chemotherapy-only strategies. DLCL patients do not need intensive CNS-directed chemotherapy.

Adolescent↗
PubMed1994

Comparison of two strategies for myocardial management during coronary artery operations.

Despite the current trend for using blood cardioplegia, ventricular fibrillation with intermittent ischemia is still used as a strategy to manage the myocardium with impressive results. These two methods of myocardial management were compared in 40 patients undergoing elective coronary artery operations using creatine kinase MB isoforms and troponin T assays. Each patient was randomized to have either cold blood cardioplegia (n = 20) or ventricular fibrillation with intermittent ischemia (n = 20) for myocardial management during the construction of distal anastomoses. Until recently, the comparison of different methods of myocardial management has been hindered by the lack of a specific and sensitive marker of myocardial damage. Analysis of creatine kinase MB isoforms (MB2, cardiac tissue form; MB1, plasma-modified form) and cardiac-specific troponin T (a structural protein) has been shown to improve the sensitivity for the detection of myocardial damage. There were no significant differences between the two groups in age, sex ratio, extent of disease, or left ventricular function. Blood samples for analysis were collected before cross-clamp application and at time intervals up to 48 hours after. Median peak creatine kinase MB2 activity was found to be significantly higher in the blood cardioplegia group compared with ventricular fibrillation (26.5 U/L versus 19.5 U/L, respectively, p = 0.04). Although median peak troponin T concentration was higher in the blood cardioplegia group, the difference failed to reach significance (2.2 ng/mL versus 1.6 ng/mL, p = 0.15).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Magnesium flux caused by coronary artery bypass operation: three patterns of deficiency.

We undertook a study to evaluate the patterns of magnesium deficiency that may develop during and following coronary artery bypass operation without cardioplegia. In 18 patients intraoperative measurements of plasma magnesium and potassium concentrations and measurements of cardiac and skeletal muscle content of these ions were taken. The changes in plasma concentrations and excretion were evaluated postoperatively. Hemodilution at initiation of cardiopulmonary bypass caused a 17.3% decrease in plasma magnesium concentration (p < 0.01), which persisted until the first postoperative day. By the fifth postoperative day the level was 19.5% greater than the preoperative value. Urinary excretion of magnesium reflected changes in plasma magnesium concentration. Cardiac muscle content of magnesium decreased by 13.3%. Plasma potassium concentration was elevated by hemodilution (p < 0.01), and muscle potassium was not depleted. We conclude that three patterns of magnesium depletion occur: hemodilution, intraoperative cellular depletion, and postoperative cellular depletion. The findings support the need for magnesium supplementation during and after cardiac operation.

Coronary Artery Bypass↗
PubMed1994

A nosocomial outbreak due to non-encapsulated Haemophilus influenzae: analysis of plasmids coding for antibiotic resistance.

An outbreak of infections with non-encapsulated Haemophilus influenzae, resistant to ampicillin, chloramphenicol, sulphonamide and tetracycline involved 13 elderly patients and three nurses on acute admission and care of the elderly wards. Thirty-two isolates were found to be indistinguishable on analysis of biotype, antibiogram, serotype and major outer membrane proteins (MOMP). Plasmids could not be identified in the original isolates but after mating with a Rec A H. influenzae recipient, the resultant transconjugates were found to harbour either a 72 kilobase pair (kB) plasmid coding for resistance to chloramphenicol, ampicillin, sulphonamide and tetracycline or a 65 kB plasmid coding for resistance to chloramphenicol, ampicillin and sulphonamide. Both plasmids yielded virtually indistinguishable restriction digest patterns. This suggests that the tetracycline resistance gene (Tc gene) is a non-essential component of one basic plasmid responsible for the multiple antibiotic resistances seen in the strains recovered during the outbreak. This illustrates the value of plasmid profiles to compare strains of non-encapsulated H. influenzae, and suggests that plasmid restriction enzyme analysis is critical.

Aged↗
PubMed1994

Endocarditis due to high level gentamicin resistant Enterococcus faecium.

We describe the first reported case in the literature of bacterial endocarditis caused by Enterococcus faecium that was highly resistant to gentamicin. The case is unusual in that it followed a successfully treated Streptococcus sanguis endocarditis. The micro-organism was susceptible only to the glycopeptide antibiotics, vancomycin and teicoplanin and to agents such as pristinamycin and daptomycin which are not routinely available for treatment. It illustrates the therapeutic dilemma posed by serious infections with such micro-organisms and supports previous observations that early heart valve replacement surgery may be necessary to achieve cure of endocarditis due to enterococci which are highly resistant to gentamicin. It further emphasises the importance of screening for high-level aminoglycoside resistance in enterococci in all life threatening enterococcal infections, including endocarditis, septicaemia and meningitis when aminoglycoside-penicillin synergy is required for successful treatment.

Aged↗
PubMed1994

Effects of solving related proofs on memory and transfer in geometry problem solving.

Three experiments investigate the relationship between memory and problem solving in the domain of geometry theorem proving. In Experiment 1, Ss memories for an original problem-solving episode were interfered with retroactively by solving a 2nd problem that had the same diagram, but no memory effects were observed that depended on the second problem's logical similarity to the original. Results suggest that the diagram is the basis for geometry problem-solving memories. Experiments 2 and 3 investigated problem-solving memories in use by examining Ss transfer to a 3rd (test) problem. As with the memory results, transfer was reduced when the 1st two problems had the same diagram relative to when they had 2 different diagrams. Transfer was reduced most in the condition with the greatest proportion of memory-interfering steps. Results suggest that the structure and quality of problem-solving memories affect problem-solving transfer.

Adult↗
PubMed1994

Acquisition of procedural skills from examples.

Three experiments were run in which Ss first memorized examples of input-output pairs and then generated the outputs for a series of new inputs by analogy to the original examples. Ss first performed these mappings by explicit analogy to an example, but with practice they learned to make these input-output mappings directly without reference to the examples. Ss sped up as a power function of practice over a day (Experiment 1) or days (Experiments 2 and 3). Ss developed a directional asymmetry such that they were slower to calculate the input from the output than the output from the input (whereas initially they had not been). Ss showed similar speed up in their ability to recall the original examples but did not show the same directional asymmetry. Initially, there was some transfer from practicing the procedure to recalling the examples, but this diminished over days.

Cognition↗
PubMed1994

A trial of elective versus on demand sclerotherapy in "poor risk" patients with variceal haemorrhage.

A prospective randomised trial of "planned" chronic injection sclerotherapy (at three weekly intervals) versus "demand" injection sclerotherapy (after variceal bleeds only) was performed in 40 patients who had endoscopically proven variceal bleeding, and who were either graded as modified Child's grade C or were more than 65 years of age. 45% of patients survived for one year and 37% for two years. There was no significant difference in survival between the groups at either one or two years (p < 0.5; p < 0.1). In the "planned" sclerotherapy group 24 gastrointestinal bleeds occurred in 11 patients over the first nine months after study entry. In the "demand" group 35 bleeds occurred in 13 patients over the first 18 months after study entry. In this small group of "poor risk" patients, planned chronic injection sclerotherapy was not associated with improved survival.

Esophageal and Gastric Varices↗
PubMed1994

Tannins in treehole habitats and their effects on Aedes sierrensis (Diptera: Culicidae) production and parasitism by Lambornella clarki (Ciliophora: Tetrahymenidae).

Tannin concentration, measured as total phenolics, varied widely in natural treehole water throughout the period of development for Aedes sierrensis (Ludlow), the western treehole mosquito. Tannic acid induced a parasitic response in free-living populations of the protozoan Lambornella clarki Corliss & Coats, an effect not entirely explained by acidity. Tannic acid concentration influenced mosquito developmental rates, survival, size, and proportion females more than food level, L. clarki parasite exposure, or any interaction of treatments for Ae. sierrensis populations reared in artificial microcosms exposed to natural conditions.

Aedes↗
PubMed1994

Endoscopic laser treatment of diffuse gastric antral vascular ectasia.

Eight patients (six women and two men) were found to have iron deficiency anaemia due to diffuse gastric antral vascular ectasia. The mean age of the patients was 74.6 years (range 57-83). All required repeated blood transfusions (mean 18 units/year) before treatment. Five patients were classified as having the 'watermelon stomach' (group A) and three the 'honeycomb stomach' (group B), according to criteria described in previous reports. All were treated using neodymium:YAG laser photocoagulation. Significant endoscopic improvement and reduction in blood requirements were noticed in group A in which only one patient required a transfusion after treatment. Results in group B were disappointing. One patient was operated on and the other two still require blood transfusions. Laser treatment was safe in both groups and no major complications were encountered.

Aged↗
PubMed1994

Chemotherapy for induction of remission of childhood acute myeloid leukemia followed by marrow transplantation or multiagent chemotherapy: a report from the Childrens Cancer Group.

PURPOSE: In an effort to evaluate the usefulness of bone marrow transplantation, the Childrens Cancer Group (CCG) initiated a multiinstitutional study comparing bone marrow transplantation versus chemotherapy after successful induction of remission for previously untreated children and young adults with acute myeloid leukemia. PATIENTS AND METHODS: From 1979 to 1983, 508 patients were entered onto this study and 490 were treated. After induction, patients with an HLA mixed leukocyte culture (MLC)-compatible sibling underwent bone marrow transplantation. Patients not eligible for bone marrow transplantation were eligible for randomization to two chemotherapy maintenance regimens. All patients undergoing bone marrow transplantation were conditioned with cyclophosphamide and total-body irradiation (TBI). Methotrexate was used to prevent or modify graft-versus-host disease (GVHD). RESULTS: Three hundred eighty-one patients achieved bone marrow remission (78%). Eighty-nine patients had an HLA/MLC-compatible sibling donor and were eligible for bone marrow transplantation, and 252 had no match. Comparison of survival estimates for patients eligible for transplantation versus not eligible at 3 years (52% v 41%), 5 years (50% v 36%), and 8 years (47% v 34%) showed a significant difference in favor of bone marrow transplantation (P < .05). Disease-free survival (DFS) demonstrated similar results. Application of a cure model to the results showed a better outcome for those eligible for transplantation (P = .04). Patients randomized between the two chemotherapy regimens did not show any significant difference between those treated with a continuous maintenance versus a cyclic regimen (P = .16). CONCLUSION: Children and young adults who successfully achieved a remission with multiple-agent chemotherapy who had an HLA/MLC-compatible donor and were thus eligible for an allogeneic bone marrow transplant had better survival than those not eligible for transplantation.

Acute Disease↗
PubMed1994

Incidence and characterization of secondary myelodysplastic syndrome and acute myelogenous leukemia following high-dose chemoradiotherapy and autologous stem-cell transplantation for lymphoid malignancies.

PURPOSE: To analyze the risk of developing myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML) following autologous bone marrow transplantation (ABMT) or peripheral stem-cell transplantation (PSCT) and to determine the impact on failure-free survival (FFS). PATIENTS AND METHODS: Patients underwent ABMT or PSCT for the treatment of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) at the University of Nebraska Medical Center. For those patients who went on to develop MDS/AML, controls were selected and a case-control-within-a-cohort study undertaken. RESULTS: Twelve patients developed MDS or AML a median of 44 months following ABMT/PSCT. The cumulative incidence (P = .42) and the conditional probability (P = .32) of MDS/AML were not statistically different between HD and NHL patients. Age greater than 40 years at the time of transplant (P = .05) and receipt of a total-body irradiation (TBI)-containing regimen (P = .06) were predictive for developing MDS/AML in patients with NHL. CONCLUSION: There is an increased risk of MDS/AML following ABMT/PSCT for lymphoid malignancies. NHL patients age > or = 40 years at the time of transplant and who received TBI are at greatest risk.

Adult↗
PubMed1994

Display of merged multimodality brain images using interleaved pixels with independent color scales.

UNLABELLED: This article reviews common methods for two-dimensional display of registered multimodality brain images and describes a software package for presentation of merged MRI and PET images that runs on a workstation with an eight-bit color display. The software package displays merged brain images from multiple modalities in a way that is readily manipulated, visually pleasing and easy to interpret. The display method used, i.e., interleaving of alternate pixels with independent color scales, is effective in producing merged images with high contrast-detail for each volume. Interleaving images from different volumes creates unusual perceptual effects, one of which is the apparent camouflage of low-contrast signals by high values in the paired volume. METHODS: The camouflage effect was thought to arise from perceptual merging of adjacent pixels. An observer experiment was conducted to investigate this tendency of high-activity PET data to obscure low-contrast detail in interleaved MRI data in spite of the digital independence of neighboring pixels. Four observers were presented with 20 combinations of signal plus background targets with uniform mask images, using a two-alternative forced-choice experimental design with 50 trials per combination. RESULTS: The psychophysical evaluation of the ability of human observers to detect the simple test objects in an interleaved image presentation indicated a statistically significant camouflage effect of one volume on the other for some combinations of target and mask. The concept of perceptual merging of adjacent pixels was able to predict which combinations caused the greatest degradations in performance. CONCLUSIONS: The image interleaving approach to the display of two-dimensional slices from registered image volumes makes efficient use of an eight-bit color display. Contrast resolution of both individual volumes is high compared with that in other techniques and the volumes are presented in familiar color scales. However, the method yields an unexpected camouflage effect that tends to obscure low-contrast signals. The practical effect of such camouflage on the interpretation of clinical images remains to be investigated.

Brain↗
PubMed1994

Impairment of nasal mucociliary clearance during bone marrow transplantation. University of Nebraska Medical Center bone Marrow Transplantation Pulmonary Study Group.

Transient mucositis occurs in almost all patients receiving bone marrow transplantation (BMT) but it is not known whether airway mucociliary transport is impaired during this period. We hypothesized that the preparative regimen associated with BMT impairs mucociliary clearance during the peri-transplant period. To test this hypothesis we determined nasal saccharine transit time (STT) and a mucositis score daily throughout the peri-transplant hospitalization in 13 patients receiving BMT. STT was prolonged in all patients at some time during the peri-transplant period and mucociliary clearance was ineffective in 12 of 13 patients for an average of 22% of the days. STT was most prolonged (about 155% of baseline) in the 2 week period following marrow infusion and correlated with the appearance of mucositis. STT returned to baseline values within 30 days after marrow infusion in all but one patient. These findings demonstrate that nasal mucociliary clearance is significantly impaired in most patients during BMT, if only temporarily. This decrease in local airway host defense may explain, in part, the increased risk of upper respiratory infections that these patients experience.

Adult↗
PubMed1994

Laparoscopic and minilaparotomy cholecystectomy: a randomized trial comparing postoperative pain and pulmonary function.

BACKGROUND: Upper abdominal surgery is associated with severe postoperative pain and a concomitant reduction in pulmonary function and oxygen saturation. Laparoscopic cholecystectomy is said to result in less postoperative pain compared with open cholecystectomy. METHODS: In a pragmatic, randomized trial, postoperative pain, opiate analgesic consumption, oxygen saturation, and pulmonary function (forced vital capacity, forced expiratory volume in 1 second, and peak expiratory flow rate) were assessed after laparoscopic (n = 67) and minilaparotomy (n = 65) cholecystectomy. RESULTS: Compared with minilaparotomy cholecystectomy, laparoscopic cholecystectomy was associated with lower linear analogue pain scores (median 40 vs 59, p < 0.001), lower patient-controlled morphine consumption (median 22 vs 40 mg, p < 0.001), a smaller reduction in postoperative pulmonary function (mean peak expiratory flow rate 64% of preoperative value vs 49%, p < 0.001), and better oxygen saturation (mean 92.9% vs 91.2%, p = 0.008). CONCLUSIONS: This study confirms that the postoperative pain and pulmonary changes associated with upper abdominal surgery are significantly reduced by the laparoscopic technique. These findings suggest that laparoscopic cholecystectomy may result in a reduced risk of postoperative pulmonary complications.

Adult↗