Search PubMed⌕ Search

Biomedical subjects

J Greenberg

Publications and source records attributed to J Greenberg.

At least 181 records · Page 10Linked to original sources
PubMed1983

A cognitive-motor network demonstrated by positron emission tomography.

The rate of local cerebral glucose metabolism was measured in subjects receiving a verbal (n = 4) and a spatial (n = 4) task. The verbal task produced greater metabolism in Wernicke's area relative to the right hemispheric homotopic region, whereas the spatial task produced greater metabolic activity in the right hemispheric homotopic region. Broca's area and its right hemisphere counterpart showed symmetrical activity during the verbal task, but there was a significant asymmetry to the right during the spatial task. Lateralized task effects were also obtained in the frontal eye fields, supporting a hypothesized neural network linking cognitive activity with motor orientation.

Adult↗
PubMed1983

Trial of low doses of aspirin as prophylaxis in sickle cell disease.

The effects of low doses of aspirin on the frequency and severity of painful vaso-occlusive crises were evaluated in children with sickle hemoglobinopathies. Aspirin was compared with placebo in 49 patients in a double-blind crossover study. Careful monitoring of patients revealed an average of 1.1 painful crises per patient year. During the 21 months of study, 70% of patients had a maximum of two painful crises, and 25% experienced four or more. The frequency and severity of crises were not affected by aspirin therapy. In view of aspirin's demonstrated effect on platelet function, we suggest that platelets do not contribute to the initiation or progression of the vaso-occlusive process.

Adolescent↗
PubMed1983

The tethered spinal cord: diagnosis by high-resolution real-time ultrasound.

High-resolution real-time ultrasonography of the lumbosacral spine was performed in 10 control patients and in six patients with suspected spinal dysraphism. The spinal cord was readily visualized in both groups. Lack of ossification of the posterior arch of the spine in normal infants and the presence of a bony defect in patients with spina bifida permit sonographic investigation of the spinal canal and its contents. It is concluded that the diagnosis of spinal cord tethering can be established rapidly by high-resolution real-time ultrasonography, which may be used in screening patients with suspected occult spinal dysraphism.

Humans↗
PubMed1983

Implant experience with unipolar polyurethane pacing leads.

A total of 905 unipolar polyurethane pacing leads have been implanted by the first author's group, between April 1978 and February 1982, with a mean implant of 1.4 years. Twelve leads were explanted and analyzed. Eleven of the explanted leads exhibited some degree of surface damage or "frosting." Of the 11, five atrial (Medtronic 6991 U) and one ventricular (Medtronic 6971) lead suffered complete insulation failure. One lead was completely free from surface damage. Clinically, insulation failure presented as muscle stimulation and/or battery depletion. Surface damage appears to be due to an environmental stress cracking (ESC) mechanism. ESC requires both a surface active agent from the hostile biological environment, and stress in excess of a threshold value. The minor surface damage or "frosting" of the eleven explanted leads was typically 10 to 15 microns deep on leads implanted about one year, although one device (15 months) had 30 micron cracks. No lead failures in this series were attributed to this shallow cracking mechanism. The severe cracking of the six Medtronic leads leading to insulin failure was thought to be due to the unusually high tensile stresses imposed by manufacturing processes and ligatures. The incidence of failure was 7% (5/74) for the Medtronic 6991 U and 0.2% (1/454) for the Medtronic 6971. Medtronic lead manufacturing processes have been modified to reduce the high residual tensile stresses and a fixation sleeve has been added to reduce ligature stress.

Arrhythmias, Cardiac↗
PubMed1982

Adjusting planning guidelines for cardiac-care units.

The principal concern of this paper is the development of procedures for adjusting the criteria currently being used for federally-legislated health planning activities. These procedures would enable the planner to account for the demographic, geographic and health-system conditions which cause variations in the need for health-care services in local communities. A case-mix method, hospital chart abstract data and demographic, geographic and health-system data from New Jersey were used to: create a list of diagnoses eligible for treatment in a Cardiac-Care Unit (CCU): select a sample of hospitals for study, and conduct a step-wise regression analysis of CCU utilization in these hospitals. It was concluded that CCU utilization was affected by factors such as the in-hospital availability of CCu beds, the type of hospital, CCU-patients' clinical severity, and the availability of ambulances and mobile intensive care units. Procedure for adjusting planning criteria to account for local conditions have yet to be developed. However, a method for using the types of results presented in this paper to develop such adjustment procedures was presented and illustrated. It is recommended that this method be used to create such adjustment procedures for the planning criteria for all hospital services and hence to assist Health Systems Agencies in rationalizing the distribution of our hospital care.

Coronary Care Units↗
PubMed1982

Factors affecting fibrinopeptide-A levels in patients with venous thromboembolism during anticoagulant therapy.

The prompt reduction of elevated fibrinopeptide A (FPA) levels (normal less than 1.3 pmole/ml) by heparin therapy in patients with thromboembolism suggests that measuring the FPA level may provide a good index of disease activity and be a useful method of monitoring therapy. Sepsis or malignancy may elevate FPA levels and coexist with thromboembolism. FPA levels were surveyed in 51 patients with thromboembolism (including 15 with concurrent sepsis or malignancy) during heparin treatment in an attempt to distinguish the effects of coexistent disease and the progression of thromboembolism. The anticoagulant effect of heparin was within the therapeutic range for 81% of the study period. In patients with thromboembolism alone and marked resolution of emboli on repeat lung scan, the mean daily FPA levels were lower than the values in patients with minimal resolution (p less than 0.005). In patients with marked resolution of pulmonary embolism or venous thrombosis and a concurrent disorder, the mean FPA level remained elevated compared to normal values in patients with thromboembolism alone. These results suggest that FPA levels monitored during heparin therapy of thromboembolism may be useful as an index of disease activity except in the presence of coexisting sepsis or malignancy.

Adenocarcinoma↗
PubMed1981

Mapping of functional activity in brain with 18F-fluoro-deoxyglucose.

The efficacy of using the 18F-fluoro-deoxyglucose (18F-DG) for measuring regional cerebral glucose utilization in man during functional activation is demonstrated. Normal male volunteers subjected to sensory stimuli (visual, auditory, tactile) exhibited focal increases in glucose metabolism in response to the stimulus. Unilateral visual hemifield stimulation caused the contralateral striate cortex to become more active metabolically than the striate cortex ipsilateral to the stimulated hemifield. Similarly, stroking of the fingers and hand of one arm with a brush produced an increase in metabolism in the contralateral postcentral gyrus compared to the homologous ipsilateral region. The auditory stimulus, which consisted of monaural listening to either a meaningful or nonmeaningful story, caused an increase in glucose metabolism in the right temporal cortex independent of which ear was stimulated. These results demonstrate that the 18F-DG technique is capable of providing functional maps in vivo in the human brain.

Adult↗
PubMed1981

A case-mix method for developing health planning criteria for hospital services.

The principal concern of this article is the inadequacy of the planning criteria currently being used by existing federally funded health planning agencies. A case-mix method was created for developing appropriate criteria. Chart-abstract data from New Jersey were used to create a list of those diagnoses eligible for treatment in the cardiac care unit (CCU), select a sample of hospitals for study and analyze the relationship between CCU bed need and CCU clinical practice. It was shown that existing bed-need criteria for CCU planning represent current CCU clinical practice patterns, which are probably not cost effective. The method was also used to develop empirical values of these criteria, which do represent cost-effective practice. It is recommended that the method be used to strengthen and update continuously all hospital-service need criteria used in current planning activities, including Plan Development and Certificate of Need Review.

Bed Occupancy↗
PubMed1981

Isolating specific auxotrophic mutants of Mycobacterium smegmatis by using vancomycin.

After inducing mutagenesis with nitrosoguanidine, we used vancomycin enrichment in isolating auxotrophic mutants of Mycobacterium smegmatis. Compared with cycloserine and penicillin G, which are also cell wall inhibitors, vancomycin, with 24 h of exposure, produced less cell lysis and a greater reduction in viable cell numbers. With vancomycin enrichment, 13 specific auxotrophs were isolated after nitrosoguanidine-induced mutation, whereas only two mutants were isolated without enrichment.

Cell Wall↗