Safety of GM-CSF in Patients with AIDS: A Review of the Literature

We performed a literature search for all clinical studies reporting outcomes in patients with the acquired immunodeficiency syndrome (AIDS) receiving granulocyte-macrophage colony-stimulating factor (GM-CSF) for any indication. Safety outcomes included human immunodeficiency virus replication, immune status, and frequency of opportunistic infections and neoplasms. Data were synthesized qualitatively. We identified 22 studies (274 patients): 12 addressed AIDS neutropenia, 8 AIDS cancer therapy, and 2 opportunistic infections. Viral burden was assessed by serum p24Ag in 15 studies. Nine reported no change in levels, three net decreases, and three net increases. All studies showing net increases involved patients receiving GM-CSF without a concurrent antiretroviral. The CD4 counts were unchanged in 5 studies, increased in 3, and not reported in 14. The incidence of neoplasms or new opportunistic infections was low. The literature suggests no increased risk of viral replication or clinical deterioration in patients with AIDS who take GM-CSF concurrently with zidovudine.     

Early detection of myocardial contusion and its complications in patients with blunt trauma

Myocardial contusion remains an elusive clinical entity, which consumes a disproportionate amount of scarce and expensive critical care resources for the purpose of cardiac monitoring. This study attempts to define a group of patients at high risk who can be identified from the available data present at the time of admission. All patients admitted with the suspicion of a myocardial contusion over a 3-year period were retrospectively studied. The records were examined for history, physical findings, electrocardiographic (ECG) results, creatine kinase levels, Injury Severity Score (ISS), and echocardiographic findings. A diagnosis of a myocardial contusion was made if patients had an ECG consistent with acute injury, increased creatine kinase-MB, or an abnormal echocardiogram consistent with acute injury. Patients were stratified into two groups: Group 1 patients satisfied the criteria for a myocardial contusion and Group 2 patients lacked sufficient evidence to substantiate this diagnosis. The records were then examined for the presence of factors available in the emergency room that might be predictive of a myocardial contusion or its complications. A total of 88 patients were evaluated; 27 of these were found to have a myocardial contusion (Group 1) with 61 patients placed in Group 2 (no myocardial contusion). Group 1 patients had an abnormal admission ECG (p less than 0.05), and an ISS greater than or equal to 10 (p less than 0.05). Multivariate analysis identified two factors predictive of a myocardial contusion: an abnormal ECG and an ISS greater than 10. When these two predictors were absent, the probability of a myocardial contusion was 1%. No predictors of a complication of a myocardial contusion were identified. These data suggest that a combination of easily obtained variables in the emergency department can be used to select a patient population at high risk for myocardial contusion. Prospective evaluation of these variables is necessary.     

MOBILITY AIDS FOR CHILDREN WITH HIGH-LEVEL MYELOMENINGOCELE: PARAPODIUM VERSUS WHEELCHAIR

The optimal method for providing mobility for children with myelomeningocele remains controversial. 39 children using a parapodium were compared with 29 children in wheelchairs. There were no significant differences between the two groups for medical complications, use of health-care services or activities of daily living, although there were differences in the patterns of complications. Children using the parapodium were more likely to develop lesions of the lower extremities, to have dislocated hips, to be more obese and to watch more television; children using wheelchairs were more likely to develop lesions of the gluteal region, to have knee-flexion contractures and to have fewer fecal accidents. The parapodium was judged by families to be less effective as a mobility aid; however, the upright posture it allows was considered extremely advantageous. A combined approach allowing upright posture and wheeled mobility would appear to be optimal.     

Contrast agents in functional MR imaging

Contrast agents have greatly expanded the role of MR imaging (MRI) to allow assessment of physiologic, or “functional,” parameters. Although activation mapping generally does not require contrast agents, other forms of functional MRI, including mapping of cerebral hemodynamics (eg, perfusion imaging), are best done with the use of contrast agents. Serial echo planar images are obtained after bolus injection of lanthanide chelates. Application of susceptibility contrast physics and standard tracer kinetic principles permits generation of relative cerebral blood volume maps. Deconvolution of cerebral blood flow and mean transit time parameters is also possible within technical limitations. By using diffusion and perfusion pulse sequences, an imaging correlate to the ischemic penumbra can be identified. Functional MRI perfusion imaging of intraaxial tumors is analogous to positron emission tomography for delineation of metabolic activity, yet may be even more sensitive to neovascularity and possesses improved image quality. Clinical applications include biopsy site selection and postirradiation follow-up. Further improvements in data analysis and map generation techniques may improve diagnostic accuracy and utility.     

Use of superparamagnetic contrast media to suppress signal from flowing spins: Preliminary experience

The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression.     

Analysis of magnetization transfer effects on T1-weighted spin-echo scans using a simple tissue phantom simulating gadolinium-enhanced brain lesions

The purpose of this study was to analyze the effect of several magnetization transfer (MT) pulse and T1-weighted spin-echo (SE) sequence parameters on lesion-to-background contrast, using a simple tissue phantom emulating the T1 relaxation and MT properties of gadolinium-enhanced brain lesions. Eggbeaters (Nabisco Inc., East Hanover, NJ) liquid egg product was doped with gadolinium in six concentrations from .0 to 1.0 mmol and cooked. The gadolinium-doped egg phantom and normal volunteer brains were studied using an SE sequence with TE = 20 msec and high power, pulsed, off-resonance MT saturation. The effects of MT pulse frequency offset (1,000–6,000 Hz), sequence repetition time (TR = 500–1,000 msec, with MT power held constant), and slice-select flip angle (60–120 degrees) on the magnetization transfer ratio (MTR) and the simulated lesion-to-background contrast were determined at the different “Intralesion” gadolinium concentrations. The MTR and lesion-to-background contrast of all materials were greatest at narrow MT pulse frequency offsets. There was an inverse relationship between gadolinium concentration and MTR and a positive correlation between the gadolinium concentration and lesion-to-background (L/B) contrast, a weak negative correlation between slice-select flip angle and L/B, and a negative correlation between TR and L/B. The relaxation properties and MT behavior of the egg phantom are close to that expected for enhancing brain lesions, allowing a rigorous analysis of several variables affecting lesion-to-background contrast for high MT power, T1-weighted SE sequences.     

Differences in leisure-time physical activity levels between blacks and whites in population-based samples: The Minnesota heart survey

Energy expenditure in leisure-time physical activity (LTPA) was measured using the Minnesota LTPA Questionnaire in 35- to 74-year-old black and white residents of Minneapolis-St. Paul, Minnesota. Estimates of the geometric mean LTPA energy expenditure were 129 and 204 kcal per day for black and white men (p<.05) and 91 and 123 kcal per day for black and white women (p<.05). The percentage of individuals expending 2000 kcal or more per week in LTPA was significantly lower in black men than white men (25 vs. 35%; p=.01) but was not different in black versus white women (18 vs. 17%). Although black men and women reported greater occupational physical activity than their white counterparts, LTPA and job activity were unrelated in all race and sex groups. In both races, LTPA energy expenditure declined with age. LTPA increased with level of formal education, and the largest LTPA difference between blacks and whites was observed in those who had a high-school diploma or less. Blacks had lower participation rates than whites in most of the individually assessed physical activities. Additional research is needed on the determinants and promoters of LTPA in population subgroups.The research was funded by National Heart, Lung, and Blood Institute Research Grant R01 HL 23727 and National Research Award T32 HL 07328-10.     

External fixation of lower limb fractures in children.

Thirty-four tibial and femoral shaft fractures in 32 children between the ages of 3 and 15 years were treated by external fixation over a 5-year period. The indications were fractures occurring in association with other major injuries and failure of conservative treatment to maintain satisfactory reduction. There was one case of delayed union and one early refracture. The overall pin track infection rate was 6%, but the rate for the tibial pins (2.1%) was much lower than for the femoral pins (10.3%). Union was achieved at an average of 11.7 weeks in the femoral fractures and 10.0 weeks in the tibial fractures. The use of external fixation is recommended for childhood femoral and tibial fractures, particularly in children with multiple injuries.