Biomedical subjects

E Gordon

Publications and source records attributed to E Gordon.

At least 127 records · Page 7Linked to original sources

PubMed1990

Enalapril induced angioedema.

A report of three patients who developed angiodema while receiving enalapril. Patient 1 came in with an 8-hour history of facial swelling after enalapril had been started 2 days earlier. The second patient came in with severe angiodema of the tongue, larynx, and glottis requiring emergency tracheostomy, hydroxyzine, and steroids. He had been treated with enalapril for 1 year. The third patient developed facial swelling within a few hours of the first dose of enalapril. Angiodema with enalapril can occur early or late in the course of therapy. A possible mechanism for this drug reaction is the potentiation of bradykinin with resultant kinin system activation.

Aged↗

PubMed1990

Intensive care in the neurosurgical unit--a review of 2,492 patients.

The experience with 2,492 patients treated during a 9-year period in a neurosurgical intensive care unit (NICU) integrated into the ordinary neurosurgical wards is reported. The basic admission criterion was the need for ventilator treatment. During the period studied, the stay in the NICU decreased from a mean of 17 to 10 days. With respect to diagnosis, the largest group was patients with brain injuries (36%), followed by subarachnoid hemorrhage (24%), other intracranial bleeding (17%), and tumors (15%). Treatment consisted mainly of controlled ventilation, the duration of which ranged between 1 and 93 days with a mean of 5 days. Invasive monitoring was done relatively seldom, primarily due to a lack of equipment and staff. The incidence of nonneurosurgical complications was low, and the clinical outcome satisfactory. Nevertheless, it is concluded that for the best care of the severely ill neurosurgical patient, a special, well-equipped NICU with an adequate number of highly qualified staff members closely attached to the neurosurgical clinic is crucial.

Journal Article↗

PubMed1990

Neuropsychological assessment and brain imaging technologies in evaluation of the sequelae of blunt head injury.

A 43 year old man with a traumatic amnesic syndrome experienced only a brief, if any, loss of consciousness following an injury to the head. Four years after this injury, his results on standard psychometric assessment were normal. Long-latency evoked response potentials results were normal, and the neurological examination and computed tomography scans were unhelpful in explaining his amnesic symptoms. He had no history of alcohol abuse, yet his neuropsychological profile was that of a Korsakoff-like amnesia with frontal lobe features. Magnetic-resonance images demonstrated evidence of extensive frontal lobe damage, while cerebral blood flow studies provided additional evidence of bilateral frontal lobe dysfunction. The case highlights the need for those giving opinions in medico-legal head trauma cases to go beyond a reliance on routine indicators, such as duration of coma, results of standard psychometric assessment and computed tomography scans, to more specialised neuropsychological evaluations and magnetic-resonance imaging scans.

Adult↗

PubMed1990

Magnetoencephalography and late component ERPs.

The recent emergence of magnetoencephalography is a development that is already yielding results. Its intrinsic sensitivity to the actual source activity, rather than to volume currents, means that its particular value lies in source localization. As well as having proven value in research relating to early evoked response and epilepsy, biomagnetic measurements have been applied to later components. For example, results for the auditory P300 potential indicate the source to lie either in the temporal cortex or the hippocampus. More definite conclusions await further development of the instrumentation. Also, there is much scope for more sophisticated analysis of the magnetic fields, of the electric potentials, or ideally of both together. This is likely to elucidate the largely unknown functional circuitry corresponding to the late components of the response.

Brain Diseases↗

PubMed1990

P300 event-related potentials in de novo Parkinson's disease.

Recent studies indicate subtle cognitive deficits in many non-demented Parkinson's disease (PD) patients. Long-latency event-related potentials (LL-ERPs) index the nature and timing of a cognitive response to a stimulus and have been used to assess cognitive function in PD. Studies to date have only assessed patients receiving long-term anti-PD therapy, which may itself affect information processing. In this study we recorded the P300 using a standard auditory oddball paradigm with a button-press response in a group of de novo patients. A P300 was absent in 2 patients and prolonged in 2 patients but there was no difference in the latency or amplitude of the P300 in the Parkinsonian group compared with the age-matched control group. The averaged P300 of the young PD group was dispersed compared with that of the young controls. Our findings suggest that the amplitude and latency of P300 elicited using the paradigm of this study are not sensitive indices for differentiating PD patients from controls. A paradigm which places a greater load on the specific cognitive deficits of PD will be investigated. The dispersion of the P300 component in the young PD group may be support for the suggestion of distinct subgroups in PD. Our findings suggest that the latency and amplitude of LL-ERP components elicited by our paradigm were not sensitive indices for distinguishing PD patients from controls. The significance of the prolonged P3-RT measure is not clear.

Adult↗

PubMed1989

A modified selective attention auditory event-related potential paradigm suitable for the clinical setting.

Auditory event-related potentials (ERPs) were recorded without practice sessions using a selective attention ERP paradigm modified from Hillyard et al. (1973) in 20 normal individuals who varied across wide ranges of age and educational background. The results concur with previous findings concerning the effects of selective attention on both the earlier and later phases of the ERP waveform. Attended stimuli elicited a larger N1 deflection compared with unattended stimuli. Processing negativity was also elicited by attended stimuli, but not by unattended stimuli. Mismatch negativity (N2) was evident in waveforms to signals as compared with standards, and a late positivity (P3) followed N2 only in waveforms to attended signals. This paradigm may be appropriate for evaluating suspected attentional dysfunctions in clinical populations.

Acoustic Stimulation↗

PubMed1989

Cerebral blood flow and metabolism during adenosine-induced hypotension in patients undergoing cerebral aneurysm surgery.

The effects of adenosine-induced hypotension on cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and cerebral lactate production, together with systemic haemodynamics, were studied in 10 patients undergoing cerebral aneurysm surgery in neurolept anaesthesia with controlled hyperventilation. CBF changes were determined in six of the patients with a retrograde thermodilution technique in the jugular vein. Hypotension was induced with a continuous infusion of adenosine in the superior vena cava. The dose range was 0.06-0.35 mg/kg/min, and this caused a 42% reduction in mean arterial blood pressure (MABP) from 79 +/- 4 to 46 +/- 1 mmHg (10.5 +/- 0.5 to 6.1 +/- 0.1 kPa) through a profound reduction in systemic vascular resistance (SVR), which amounted to 61%. No significant change occurred in CBF. Whole body AV-difference of oxygen was decreased by 37%, and cerebral AV-difference by 28%, corresponding to reductions in whole body oxygen uptake and CMRO2 of 16 and 17%, respectively. Cerebral AV-difference of lactate did not change. In the posthypotensive period MABP was increased by 10%, together with a minor increase in CBF (15%). It is concluded, that adenosine-induced hypotension at MABP levels between 40-50 mmHg (5.3-6.7 kPa) does not affect cerebral oxygenation unfavourably, and may even offer a protective effect by reducing cerebral oxygen demand. The slight CBF increase in the posthypotensive period was probably secondary to an increase in MABP together with a blunted autoregulation, but in no case was this effect considered to be harmful for the patient.

Adenosine↗

PubMed1989

Regional cerebral blood flow measurements in the diagnosis of dementia.

The Xenon-133 regional cerebral blood flow technique (rCBF) was used to assess cortical perfusion in a group of 15 elderly patients (mean age = 79.1, SD = 8.7) with a probable diagnosis of Dementia of the Alzheimer type (DAT). Nine had mild DAT and six were in the moderate stages of DAT. These patients were compared with 15 age and sex matched normal elderly controls (mean age = 75.1, SD = 5.6). RCBF was measured in each patient and control at rest with eyes closed. The DAT patients had significantly lower mean global CBF than normal controls (t = -4.63, p less than 0.0001). In addition, a further 15 normal elderly subjects aged 60 to 92 were assessed and combined with the original 15 to allow calculation of a normal range of rCBF for elderly individuals. Seventy-three per cent of the DAT patients fell below the lower limit of the normal range (39.3 - 59.3 ISI units). These results show the possible usefulness of rCBF as an aid in the diagnosis of early DAT.

Aged↗

PubMed1989

The P300 event-related potential and regional cerebral blood flow in patients with Alzheimer's disease.

A number of studies have reported that an abnormal delay in the latency of the P300 event-related potential (ERP) is characteristic of the majority of patients with a dementing process. Another body of research suggests regional cerebral blood flow (rCBF) is significantly reduced in Alzheimer's disease (AD). No previous study has compared the effectiveness of these 2 measures in identifying the same patients with AD. Furthermore, most of the studies on which the above findings are based examined patients in the moderate to severe stages of the disorder. In this study we examined P300 latency and rCBF in 10 patients with mild to moderate Alzheimer's disease, and compared their responses with those of normal subjects of similar age. The P300 component was not evident in 2 of the patients: the remaining 8 had a latency within normal limits for their age. On the other hand, 8 of the patients had abnormally reduced rCBF. These results suggest rCBF measures may be useful for identifying AD in its early stages.

Aged↗

PubMed1989

The relationship between reaction time and latency of the P300 event-related potential in normal subjects and Alzheimer's disease.

The latency of the P300 event-related potential is though to reflect the time it takes to conclude that a task-relevant stimulus has been presented, i.e. it is an index of cognitive processing time. Reaction time (RT) also reflects cognitive processing time, but additionally reflects the time taken physically to respond to the stimulus. If serial models of information processing are correct, then the P300 latency must be less than RT, and a positive correlation between the 2 measures is to be expected. We examined these hypotheses in 100 normal subjects aged from 18 to 92 years. The P300 component elicited via a 2-tone discrimination task, and RT to the task-relevant tones was measured simultaneously. The resulting correlation between these measures was weak (r = 0.26, p greater than 0.05), and there were instances in which RT preceded the P300 latency. These results are consistent with parallel rather than serial models of information processing. Fifteen patients with Alzheimer's disease were also examined. Three had an abnormally delayed P300 latency, and 7 had abnormally delayed RTs compared with age-matched controls. Simultaneous measurement of the P300 latency and RT may thus help resolve whether dysfunction is evident in neuronal networks concerned with stimulus evaluation or in those concerned with response execution.

Adult↗

PubMed1989

A hierarchical model of opiate addiction. Failures of self-regulation as a central aspect of substance abuse.

In this paper, we first examine and recast the research literature on opiate addiction in the light of a hierarchical model of self-organization. The hierarchical model consists of five modes of psychological and psychobiological functioning defined epigenetically. Research and theories of opiate addiction are classified as to their primary modal emphases. We then describe failures of self-regulation as particular vulnerabilities along the first three modes of the hierarchy. A measure of this construct, the Scale for Failures in Self-Regulation (SFSR), a projective measure that utilizes Thematic Apperception Test responses, is introduced for the study of opiate addicts. The SFSR was administered to normal and opiate-addicted subjects in order to examine the predictive and explanatory power of the hierarchial model. A multivariate analysis of variance showed the addicts to have greater difficulties in self-regulatory functioning than normal subjects. In terms of the hierarchical model, the implications of these findings for the questions of severity of illness, psychotherapy technique, and future research are discussed.

Adult↗

PubMed1989

The renal carcinogenic effect of Merpafol in the Fischer 344 rat.

Three groups of Fischer 344 rats were fed Merpafol (Makhteshim, Israel), an agricultural fungicide, in increasing concentrations for a period of 2 years. A control group was maintained under identical conditions, but without the addition of the fungicide in the diet. A range of nonneoplastic and neoplastic lesions were observed in the kidneys of rats fed Merpafol. The histogenesis of the renal tumors is discussed in relation to chemical-induced epithelial hyperplasia and cystic tubular dilation. Comparative aspects of renal cyst development and carcinoma in humans are also discussed.

Adenoma↗

PubMed1988

Use of mannitol during neurosurgery: interpatient variability in the plasma and CSF levels.

An i.v. infusion of mannitol was given over 15 min to 12 patients before they underwent intracranial surgery under general anesthesia. Samples of blood, CSF and urine were taken over 4 h. Mannitol disappeared from plasma in a bi-exponential manner. The mean maximal plasma concentration was 4.08 mg/ml at 15 min, and at 4 h it had declined to 0.53 mg/ml. The mean distribution rate constant was 11.2 h-1, corresponding to a plasma distribution half-life of 0.11 h. The mean elimination rate constant was 0.41 h-1, the plasma half-life was 2.2 h, the central distribution volume was 16.3 l, and total plasma clearance was 100.4 ml/min. The mean concentration of mannitol in CSF during the 4 h period increased up to 0.10 mg/ml. There were marked interindividual differences in the concentration ratio blood/CSF, and the CSF concentration varied 7.5 fold between patients. Optimal use of mannitol during neurosurgery requires further prolonged study of its pharmacokinetics.

Adult↗

PubMed1988

The effect of isoflurane on cerebrospinal fluid pressure in patients undergoing neurosurgery.

Ten patients with intracerebral tumours (TC) and 13 patients with subarachnoid haemorrhage (SAH) from a ruptured cerebral arterial aneurysm were studied before intracranial surgery, and during a 3-h postoperative period. Cerebrospinal fluid pressure (CSFP) determined by an intraventricular (TC group) or intraspinal (SAH group) catheter, and mean arterial blood pressure (MABP) were recorded under neurolept anaesthesia (control) followed by isoflurane inhalation. These two measurements were performed during normocapnia. A third measurement was made during hypocapnia, with unchanged isoflurane concentration. After the experimental period, isoflurane remained the main anaesthetic agent throughout the surgical procedure. After recovery from anaesthesia, the patients were monitored with CSFP and blood pressure during the first postoperative hours, and the quality of breathing was assessed by hourly blood-gas analyses. The results show that isoflurane causes a 10-14% reduction of MABP with no further changes during hyperventilation. Mean CSFP increased 27% in the TC group, and 12% in the SAH group after isoflurane induction and decreased from these levels by 29% during hyperventilation in both groups. Consequently, the impact on cerebral perfusion pressure (CPP) by isoflurane was a 19% and 21% mean decrease in the TC and SAH group, respectively. Controlled hyperventilation reduced this effect by partially restoring control CPP values, with 8% and 14% increase, respectively. In the postoperative follow-up, all patients had normal breathing and blood pressure with low values of CSFP. It is concluded that isoflurane can be used in intracranial surgery with adequate safety if combined with controlled hyperventilation.

Adult↗

PubMed1988

The P300 event related potential component in the diagnosis of dementia.

Several studies have suggested that delays in the latency of the P300 ERP component are highly sensitive and specific to dementia and that ERP measurements may become a useful clinical tool in aiding diagnosis. This study examines the sensitivity of P300 measurements to dementia and addresses several methodological issues that limit previous research. Twenty-four patients with dementia diagnosed according to ICD-10 criteria were compared with 100 normal controls, 31 of whom were older than 60. An auditory oddball paradigm was employed to elicit the P300. Mean P300 latency did not differ significantly between the two groups. When individual subjects were examined only 13% of patients with dementia fell outside the two standard error band of the regression of P300 latency on age derived from controls. Thus, this study has not demonstrated clinically useful abnormalities of the P300 component in dementia.

Adolescent↗

PubMed1987

Effective tumor immunotherapy directed against an oncogene-encoded product using a vaccinia virus vector.

We have constructed a vaccinia virus recombinant that expresses the extracellular domain of the rat neu oncogene-encoded protein, a 185-kDa transmembrane glycoprotein termed p185. Strain NFS mice immunized with this recombinant virus developed a strong antibody response against the neu oncogene product and were fully protected against subsequent tumor challenge with neu-transformed NIH 3T3 cells. No tumor immunoprotection was found when recombinant virus-immunized mice were challenged with Ha-ras-transformed NIH 3T3 cells. These data indicate that immunization with a single oncogene-encoded antigen can fully and specifically protect animals against tumor cells bearing this antigen.

Animals↗

PubMed1987

A segmentational analysis of prescription drug information seeking.

Drug information-seeking proclivities were examined using data from a telephone survey of 835 individuals who had obtained new outpatient prescriptions within the previous 4 weeks. Factor analytic and clustering techniques were used to segment patients based on the source and nature of drug information received in conjunction with the prescription. A four-cluster solution appeared to represent the most stable, distinct, yet homogeneous solution for the data. The groups were named "physician reliant" (40%), "pharmacist reliant" (19%), "questioners" (7%), and "uniformed" (34%). The four groups were compared for demographic, situational, and attitudinal differences. The physician-reliant group appeared most satisfied with the direct counseling of the doctor. Although this group may have sought additional information, the information appeared to reinforce the physician's directions. The pharmacist-reliant group often obtained prescriptions at independent pharmacies and tended not to rely on magazines or reference books for additional information. The questioners were often taking multiple medications. This group tended to seek out reference information from nonprofessional sources and reported several barriers to seeking information from professionals. The uninformed group was the oldest, tended to receive little information, and was more likely than the other groups to agree that one need not ask questions if one trusts the doctor. Different types of patient education programs were recommended as appropriate for each of the four groups. Motivational messages directed to the uninformed segment appeared to be the largest unmet need in patient-oriented prescription drug education.

Adult↗

PubMed1987

ECG abnormalities in patients with subarachnoid haemorrhage and intracranial tumours.

The incidence of and possible factors influencing ECG abnormalities were analysed in one patient group with subarachnoid haemorrhages (n = 406) and another with intracranial tumours (n = 400). The highest incidence of each ECG abnormality was always found in the patients with subarachnoid haemorrhages. In this group an ECG pattern, possibly attributable to the cerebral disease and comprising abnormalities of the T and U waves and prolongation of the Q-Tc interval, was frequently identified.

Adolescent↗