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Biomedical subjects

B J Erickson

Publications and source records attributed to B J Erickson.

54 records · Page 3Linked to original sources
PubMed1997

Value of magnetic resonance imaging in assessing efficacy in clinical trials of multiple sclerosis therapies.

Magnetic resonance imaging (MRI) has become an important technique for monitoring the effectiveness of putative treatments for multiple sclerosis (MS) because of its high sensitivity, objectivity, and noninvasive nature. Its importance as a surrogate measure of disease, however, is an issue that is more difficult to validate than might seem to be the case. In this review, we describe the role of MRI in the assessment of putative therapies for MS. New magnetic resonance techniques and methods of image analyses aimed at better demonstrating the nature and extent of disease are discussed, and the role of MRI in published MS therapeutic trials is examined. MRI is a frequently used secondary outcome measure for putative treatment strategies for MS. Although it is sensitive to changes in the inflammatory component of the MS disease process, poor correlation has been noted between MRI findings and long-term patient outcome. There is a widespread expectation that new magnetic resonance techniques--such as fluid-attenuated inversion recovery, magnetization transfer imaging, and magnetic resonance spectroscopy--will ultimately be useful for characterization of pathologic changes within the MS lesion and more generally of the MS disease process. Whether magnetic resonance changes seen in experimental therapies predict the long-term clinical course of the disease remains to be determined.

Clinical Trials as Topic↗
PubMed1996

Acute intoxication and substance abuse among patients presenting to a psychiatric emergency service.

It is common for patients to arrive at the Psychiatric Emergency Service (PES) under the influence of a variety of drugs. The purpose of this study was to 1) determine what impact there was on the PES of patients who arrive after engaging in substance abuse within the 24 hours prior to arrival; and 2) describe some of the parameters associated with substance abuse and mental illness in the PES setting. Consecutive evaluations done at the PES during the study month were reviewed retrospectively utilizing the extensive material collected in the screening chart. Of the 294 evaluations, 32.0% (n = 94) were on patients with acute intoxication and 17.0% (n = 50) had a primary diagnosis of substance abuse or dependence; 49 of 50 presented with active substance abuse. Schizophrenic and personality disorder patients presented with significant levels of acute intoxication (25.2%, 26/103), whereas substance use rate was quite low for patients with affective disorder, adjustment disorder, and other diagnoses. Alcohol was the overwhelming drug of choice by all diagnostic groups, making it difficult to determine group differences in choice of drug. Both the univariate and multivariate studies presented demonstrate that regardless of diagnosis, the impact of substance abusing patients is substantial. They present with high acuity (usually acutely suicidal), require high levels of behavior management, and spend more time in the PES. However, they have much less need for psychiatric hospitalization. In contrast, the patients presenting with psychosis also have a high rate of behavior management needs, but these patients are very likely to be hospitalized. These findings suggest that an important role for the PES is a "filter" to triage patients to the appropriate treatment setting and that this role is fulfilled when the PES is able to provide sufficient time and resources for evaluation and/or stabilization.

Adolescent↗
PubMed1996

Characteristics of managed care patients in a psychiatric emergency service.

Managed care programs establish procedures to help their patients avoid use of psychiatric emergency services. To determine whether managed care patients who do visit the emergency service do so primarily for hospitalization and have briefer contacts with the service because of preapproval for hospitalization, records were examined for 293 patients who visited a psychiatric emergency service; 69 were enrolled in a managed care plan. The findings did not confirm the expectations: many managed care patients received crisis services and were referred for outpatient care. The non-managed-care group had more psychotic and substance use disorders, required more emergency community intervention, and had more previous psychiatric hospitalizations.

Ambulatory Care↗
PubMed1995

Crisis hospitalization in a psychiatric emergency service.

Crisis hospitalization has both an affirmative rationale in the community movement and a secondary rationale of cost containment. Brief hospitalization within the psychiatric emergency service offers intensive treatment and a rapid return to the community for the patient and is cost-effective for the mental health system.

Adult↗
PubMed1994

Initial clinical experience in MR imaging of the brain with a fast fluid-attenuated inversion-recovery pulse sequence.

PURPOSE: To evaluate fast fluid-attenuated inversion-recovery (FLAIR) technique for imaging brain abnormalities. MATERIALS AND METHODS: A fast FLAIR sequence was developed that provided 36 5-mm contiguous sections in 5 minutes 8 seconds. Resulting images were compared with dual-echo T2-weighted spin-echo images of 41 consecutive patients with brain abnormalities. RESULTS: Contrast and contrast-to-noise ratios (C/Ns) (for contrast between the lesion and background and between the lesion and cerebrospinal fluid) for fast FLAIR exceeded the corresponding values for T2-weighted spin-echo images for all but the second-echo lesion-to-background C/N. Fast FLAIR provided equivalent or greater overall lesion conspicuity and enabled greater lesion detection in 98% and 100%, respectively, of the evaluations. Fast FLAIR images more often had image artifact, but this did not interfere with image interpretation in a significantly (P < or = .05) greater number of evaluations. CONCLUSION: Fast FLAIR provides images that are superior to proton-density- and T2-weighted images for many image quality criteria.

Artifacts↗
PubMed1993

Experimental transmission of an apparent viral pneumonia in conventional and gnotobiotic pigs.

Endemic pneumonia in five- to eight-week-old pigs induced microscopic lesions of proliferative interstitial pneumonia which were compatible with a viral aetiology. The disease was transmitted experimentally to conventional and gnotobiotic pigs by means of a lung homogenate filtered through a 0.22 micron filter. No common viral respiratory pathogens of pigs were isolated. Two types of virus particles were observed in cell culture by electron microscopy; one was about 70 nm in diameter and had an envelope and short surface spicules, the other also had an envelope, was elongated, pleomorphic, measured 80 x 320 nm and was coated by antibodies.

Animals↗
PubMed1993

Determination of 10-20 system electrode locations using magnetic resonance image scanning with markers.

We determined locations of 33 scalp electrodes used for electroencephalographic (EEG) recording by placing markers in the positions determined by the 10-20 system and performing magnetic resonance image (MRI) scanning on volunteer subjects. Small Vaseline-filled capsules glued on the scalp with collodion produced easily delineated regions of increased signal on standard MRI head images. Measurements of each capsule's coordinates in 3 dimensions were made from MRI scans. A spherical surface was fitted through the marker positions, giving an average radius and an origin (center of sphere). The coordinate axes were rotated to ensure that electrode Cz was on the z-axis and that the y-axis was oriented in the posterior-anterior direction. Two spherical (angular) coordinates were determined for each electrode. Spherical electrode coordinates for different subjects differed by less than 20 degrees in all cases. An average and standard deviation of the spherical coordinates were calculated for each electrode. Standard deviations of several degrees were obtained. The average spherical coordinates obtained were close to those expected on the basis of applying the 10-20 system of placement to an ideal sphere. These measurements provide data necessary for various analyses of EEG performed to help localize epileptic foci.

Brain↗
PubMed1993

Crisis hospitalization on a psychiatric emergency service.

The availability of short-stay beds for brief admissions to a Psychiatric Emergency Service (PES) is a model that meets a variety of patient and system needs, allowing time to develop alternatives to hospitalization or gain diagnostic clarity, serving a respite function, providing a hospital setting that does not gratify dependency needs, and relieving inpatient census pressures. An eight-bed service for brief inpatient stays of up to 3 days was developed on a PES which serves a large nine-country catchment area in northeastern New York State. Admissions to this unit would otherwise have gone to a medical school teaching hospital psychiatric unit or a state psychiatric center. Fifty-one consecutive admissions were studied. The majority of patients were dischargeable in the short time frame and did not require transfer for longer-term care. The patients as a group showed improvement in psychiatric symptomatology and rated high satisfaction with the program. Most patients were diagnosed with schizophrenia or personality disorder (PD). Suicidality and substance abuse were frequent. The PD patients had a strong association with suicidality and some association with substance abuse, whereas the schizophrenics had more psychiatric symptomatology. PD patients were more likely to be discharged, leading us to propose a rationale for why this group may be uniquely suited to this approach. The study was replicated after a year on another sample of 51 consecutive admissions, confirming the earlier results and providing a 1-year follow-up on the program.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Three-dimensional reconstruction of the temporal bone.

Study of the complex anatomy and pathology of the temporal bone has traditionally used microscopy which permits analysis in only two dimensions. Recent advances in bioimaging technology have permitted visualization and reconstruction of computed tomography images in three dimensions. We have developed a technique that applies this technology in the imaging and reconstruction of human temporal bones. Data taken from serial histologic sections of the temporal bone are entered into a computer. The sections are edited and, through the use of specially developed software, a realistic three-dimensional reconstruction is produced. The reconstructed image can be rotated along any of three axes, and structures within the temporal bone can be isolated for more detailed analysis. Applications for the study of pathologic conditions of the temporal bone will be discussed.

Adult↗
PubMed1986

Implementation of the gas chromatographic/mass spectrometric peptide sequencing program PEPALG on a personal computer for off-line analysis.

The gas chromatographic/mass spectrometric peptide sequencing program PEPALG has been implemented in both FORTRAN and PASCAL on a personal computer for convenient off-line analysis. The availability of PEPALG in a microcomputer-based version of both FORTRAN and PASCAL should now allow ready access to this powerful protein sequencing technique by any interested laboratory.

Amino Acid Sequence↗
PubMedDate not supplied

An analysis of risk from exposure to aldicarb using immune response of nonuniform populations of mice.

The immunomodulation response of mice to low levels of aldicarb in drinking water was investigated in four series of studies. The splenic plaque forming cell (PFC) response to red sheep cells were measured for treatment levels of 0.01 to 1,000 ppb (micrograms/kg). Based on their beginning and end body weights, the animal populations were uniform in all series of tests, but based on their net body weights and PFC counts they were highly nonuniform in the 30 and 60 day tests and uniform in the 90 and 180 day tests. The mean PFC counts for animals in each treatment were calculated and compared with the mean PFC counts for animals in the controls in all four series of tests. This approach ignores the variability and nonuniformity in the animal population. The outcomes using this approach were stimulatory for the 30 and 60 day tests and inhibitory for the 90 and 180 day tests. An alternative approach was developed based on the analysis of the distributions of the relative PFC counts of each animal in a treatment with each animal in a control, and specifically addresses the variability and nonuniformity in animal population as integral parts of the analysis. The distribution peaks were estimated by maximum likelihood and kernel/bootstrap procedures and were used to summarize the tests. The outcomes were consistently inhibitory, indicating immune suppression. The outcome of this approach converged to the outcome of the mean PFC approach for the 90 and 180 day tests where the animal populations were uniform.

Aldicarb↗
PubMedDate not supplied

The disruptive behavior disorders in the psychiatric emergency service.

Many children and adolescents presenting to the Psychiatric Emergency Service (PES) are diagnosed with the Disruptive Behavior Disorders (DBD), Conduct Disorder (CD), and Oppositional Defiant Disorder (ODD). Sometimes it may be difficult to reliably diagnose these disorders in the PES setting. Given these limitations, a large database of 6 years of PES visits showed 314 patients with DBD compared with 1625 without DBD. More DBD patient visits required the intervention of police and/or the mobile crisis team. These patients are more likely to have additional diagnoses of depression and attention deficit hyperactivity disorder, be in current treatment, or involved with court or the correctional system. They are less frequently referred by other emergency services such as medical ERs. DBD patients do not require emergency medication or psychiatric hospitalization any more frequently than other youngsters presenting to the PES. In the PES setting there is little differentiation between the CD and the ODD population. A more detailed study of the presenting symptomatology of the DBD vs non-DBD patients revealed that DBD patients showed over twice as many disruptive behavior symptoms. Fights and defiance were present significantly more frequently than in controls, with a trend toward increased frequency of bullying and stealing. The clinical and public mental health implications of these findings are discussed.

Adolescent↗
PubMedDate not supplied

Correlation of single photon emission CT with MR image data using fiduciary markers.

PURPOSE: To describe our approach to mapping the functional information provided by single photon emission computed tomography (SPECT) onto the anatomic template provided by MR, and to determine both the number of markers required to achieve accuracy and the impact of voxel shape on accuracy. METHODS: Point-to-point iterative minimization using externally fixed fiducial markers was involved and computer simulations were performed. Two types of validation studies were performed using a phanton using a phantom of known dimensions. First, the spatial distortion that may be present in MR was investigated for spin-echo and gradient-recalled echo images. Next, the accuracy with which the SPECT image could be transformed to match the MR template was analyzed. The method is also demonstrated in four cases of patients with epilepsy. RESULTS: Computer simulations indicated that for voxel dimensions we expected to use, eight fiduciary markers would consistently produce acceptable accuracy. Simulations also showed that more isotropic voxels would be more accurate if voxel volume is held constant. The spatial accuracy of both spin-echo and gradient-recalled echo images of a phantom was accurate to within 3 mm. When the SPECT image of the same phantom was correlated with the MR image using this technique, internal marker errors were never greater than 3 mm, and the mean error was 2.2 mm. CONCLUSIONS: Images from different modalities can be accurately correlated using multiple fiduciary markers. SPECT and MR images of the given dimensions can be correlated to within 3 mm. The technique aids in clarification of the nature of SPECT perfusion abnormalities and in their anatomic localization.

Brain↗