Biomedical subjects
R Roemer
Publications and source records attributed to R Roemer.
Single-voxel proton magnetic resonance spectroscopy of the pons and cerebellum in patients with schizophrenia: a preliminary study.
Magnetic resonance spectroscopy (MRS) is a non-invasive functional imaging technique that can measure various brain tissue metabolites such as N-acetylaspartate (NAA), choline (Cho), creatine-phosphocreatine (Cr), myo-inositol (mI) and other metabolites. Morphological studies have indicated the pons and cerebellum as possible sites of abnormal functioning in schizophrenic patients. This study examines schizophrenic patients for the presence of abnormalities in proton MRS (1H-MRS) measured metabolites in two regions of the posterior fossa. Twelve schizophrenic patients and eight non-schizophrenic control subjects were studied by measuring the ratios of NAA/Cr, Cho/Cr and mI/Cr from 1H-spectra obtained from the pons and right or left cerebellum using an integrated MRI/MRS protocol. Spectra were obtained from a voxel in the pons and voxels from the left and/or right lateral cerebellum. Data were analyzed in the absorption mode and fitted to Lorentzian lineshapes using a Marquart algorithm. Significantly lower NAA/Cr ratios were found in the pons of schizophrenic patients than in the control subjects, but not in the cerebellum. This study is the first to measure brain tissue metabolites using 1H-MRS in the pons and cerebellum of schizophrenic patients. Significant alterations of 1H-MRS metabolites may suggest the involvement of the posterior fossa as a part of the pathological substrate underlying schizophrenia.
The efficacy and safety of maintenance ECT in geriatric patients.
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Evoked potential topography in unmedicated and medicated schizophrenics.
The main purposes were to determine whether: (1) evoked potential (EP) topography differs from normal in schizophrenics; (2) EP topography is altered by psychotropic drugs. Unmedicated (n = 72) and medicated (n = 57) schizophrenics were compared with age- and sex-matched non-patients and with one another. EPs to left and right median nerve, visual pattern and auditory stimuli were recorded from 15 leads. EP data were reduced by principal component analysis (PCA) of EP waveforms, with separate PCAs for later and earlier poststimulus times; 32 factors were extracted. Factor scores, based on factor structure of 195 non-patients, were computed for all subjects. Topographic effects were evaluated by ANOVAs on Z-transformed factor scores. The results were: (1) topographies differed between groups in about one-third of the factors, but variables yielding effects differed between comparisons; (2) topographic differences from normal in unmedicated patients converged at left temporoparietal (higher in schizophrenics) and right fronto-central-temporal areas (lower in schizophrenics); (3) similar convergence was absent in medicated patients; (4) most medicated vs unmedicated patient topographic differences persisted in groups matched for psychopathology. Results appear consistent with "focal cortical arousal" of the left posterior quadrant in schizophrenics (Morihisa and Duffy, 1986) and suggest that medication alters EP topography.
Multi-point feedback control system for scanned, focused ultrasound hyperthermia.
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Global health, national development, and the role of government.
In spite of extreme differences in health status between the more developed and less developed countries, trends of infant mortality and life expectancy show substantial improvements in both types of country between 1950 and 1980. These improvements may be attributed to three types of change: 1) socio-economic development with decolonization, increased industrialization, growth of gross domestic product, urbanization, the gains of women, and enhanced education; 2) cross-national influences due to greater international trade, the spread of technology, and widespread affirmation of human rights; and 3) national health system development through expanded governmental health programs. Further improvements will depend on greater strength in public sector health services rather than private sector services which aggravate inequities.
Options, strategies, and priorities for legislation to control smoking.
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Fighting the smoking epidemic: legislative and economic weapons.
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Future directions for public health.
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The right to health care--gains and gaps.
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A comparative analysis of thermal blood perfusion measurement techniques.
The object of this study was to devise a unified method for comparing different thermal techniques for the estimation of blood perfusion rates and to perform a comparison for several common techniques. The approach used was to develop analytical models for the temperature response for all combinations of five power deposition geometries (spherical, one- and two-dimensional cylindrical, and one- and two-dimensional Gaussian) and three transient heating techniques (temperature pulse-decay, temperature step function, and constant-power heat-up) plus one steady-state heating technique. The transient models were used to determine the range of times (the time window) when a significant portion of the transient temperature response was due to blood perfusion. This time window was defined to begin when the difference between the conduction-only and the conduction-plus-blood flow transient temperature (or power) responses exceeded a specified value, and to end when the conduction-plus-blood flow transient temperature (or power) reached a specified fraction of its steady-state value. The results are summarized in dimensionless plots showing the size of the time windows for each of the transient perfusion estimation techniques. Several conclusions were drawn, in particular: (a) low perfusions are difficult to estimate because of the dominance of conduction, (b) large heated regions are better suited for estimation of low perfusions, (c) noninvasive heating techniques are superior because they have the potential to minimize conduction effects, and (d) none of the transient techniques appears to be clearly superior to the others.
Legislation to control smoking: leverage for effective policy.
The concern of the 6th International Symposium on Prevention and Detection of Cancer with legislation to curb smoking reflects the growing recognition of the contribution that the law can make to controlling the promotion and use of one of the most serious health hazards of modern times--tobacco. Oncologists, with their intimate knowledge of the link between smoking and disease, are a powerful ally in this world-wide struggle.
ERPs and psychopathology. II. Biological issues.
We have briefly covered important issues and considerations in four topic areas likely to be of use to the ERP researcher who is also interested in biological psychiatry. We cannot ignore diagnosis because of its basic role in the field of psychiatry. Although there are reliability problems, especially in the field of psychiatric diagnosis, ERPs may help in the painstaking task of validating diagnosis based on behavioral observation. In addition, the ERP researcher can use diagnosis to obtain potentially more homogeneous samples of patients so as to reduce between-subject error variance in studies. We have considered research areas like PET scan and CT scan which provide data of more anatomical precision than ERPs for deep neurological sites. While the potential may be there, it is essentially unrealized as yet. Finally, neurochemistry and psychopharmacology seem to be the areas most likely to bear fruit in the immediate future. If this potential is to be realized, it is necessary to formulate new questions and a new methodology to handle these questions. An important question, for example, is whether a biological profile is a more useful criterion than a behavioral profile for predicting response to pharmacological intervention. In biological psychiatry, this question is a human suffering issue of considerable importance.
Legislation aimed at curbing the world smoking epidemic.
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Private management of California county hospitals: expectations and performance.
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Private management of public hospitals: the California experience.
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Health service developments: their impact on regulation and functions of rehabilitation personnel.
The boundaries and responsibilities of rehabilitation personnel are defined by direct regulation of personnel through licensure and certification and by indirect regulation through the system in which the health professions work. New regulatory measures governing health personnel in the United States and other countries indicate a trend towards innovative roles and increased autonomy for rehabilitation therapists. Current developments in the American health care system will have important impacts on the functions, education, and credentialing of members of the rehabilitation team.
Equity in abortion services.
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