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E Wallace

Publications and source records attributed to E Wallace.

At least 19 recordsLinked to original sources
PubMed1997

The philosophy of psychiatry: who needs it?

Many a psychiatrist has said that he did not want to burden himself with a philosophy and that this science had nothing to do with philosophy. But the exclusion of philosophy would nevertheless be disastrous for psychiatry: firstly, if we are not clearly conscious of our philosophy we shall mix it up with our scientific thinking quite unawares and bring about a scientific and philosophic confusion. Secondly, since in psychopathology in particular the scientific knowledge is not all of one kind, we have to distinguish the different modes of knowing and clarify our methods, the meaning and validity of our statements and the criteria of tests- and all this calls for philosophic logic ... To sum up: If anyone thinks he can exclude philosophy and leave it aside as useless, he will be eventually defeated by it in some obscure form or another.

Culture↗
PubMed1996

Reproducibility of iodine-123-beta-CIT SPECT brain measurement of dopamine transporters.

UNLABELLED: Iodine-123-beta-CIT has been used as a probe of monoamine transporters in human and nonhuman primates utilizing SPECT. To assess the utility of this tracer for measurement of striatal dopamine (DA) transporters in human disease, we studied the test/retest variability and reliability of SPECT measures obtained after bolus injection of [123I]beta-CIT 0-7 hr (Day 1) and 18-24 hr (Day 2) after administration. METHODS: For the Day 2 study, seven healthy humans (4 men, 3 women; aged 19-74 yr) participated in two [123I]beta-CIT SPECT scans separated by 7-14 days. Subjects were imaged at 18, 21 and 24 hr postinjection of 370 MBq (10 mCi) [123I]beta-CIT. Two outcome measures were evaluated: (a) the ratio of specific striatal (activity associated with DA transporter binding) to nondisplaceable uptake, also designated V"3 and (b) the total, specific striatal uptake (%SSU) expressed as a percentage of injected radiotracer dose. Test/retest variability associated with V"3 and total specific striatal uptakes were compared for scans acquired at 18, 21 and 24 hr with 24 hr only postinjection scans. For the Day 1 study, three of the subjects participated in two kinetic studies of [123I]beta-CIT uptake. A three-compartment model was used for determination of konBmax and binding potential (BP = Bmax/Kd) and the reproducibility of the measures assessed. RESULTS: In the Day 2 study, both outcome measures demonstrated excellent test/retest reproducibility with variability of V"3 = 6.8 +/- 6.8% and percent striatal uptake = 6.6 +/- 4.3% using data acquired from all time points. There were no significant differences in variability for the two outcome measures obtained. The intraclass correlation coefficient rho was 0.96 and 0.98 for V"3 and %SSU, respectively. Considering the 24 hr postinjection scans only, there was a nonsignificant trend toward lower test/retest variability for %SSU compared to V"3 (6.6 +/- 4.2% and 12.8 +/- 9.0%, respectively). The test/retest variability for the Day 1 kinetic modeling data showed marked differences depending on the fitting strategy and assumptions about the reversibility of [123I]beta-CIT in striatum. Using a model that assumed a low, fixed value for reversible striatal binding (k4) produced low variability (12 +/- 9%). CONCLUSION: These data suggest that SPECT imaging performed at either 0-7 hr or 18-24 hr after [123I]beta-CIT injection permits calculation of reliable and reproducible measures of dopamine transporters and supports the feasibility of using [123I]beta-CIT in serial evaluation of human neuropsychiatric disease.

Adult↗
PubMed1995

Pamidronate treatment of the neurologic sequelae of pagetic spinal stenosis.

Spinal stenosis is a serious complication of Paget's disease of bone. Surgical decompression has a high complication rate and is not always effective. Medical therapy with bisphosphonates is established treatment in other forms of Paget's disease. To our knowledge, this is the first report of the use of intravenous pamidronate disodium as the sole treatment of lower limb weakness attributable to pagetic spinal stenosis. Our patient has been restored to independent living and has maintained his remission, with repeated treatment, for more than 5 years.

Aged↗
PubMed1995

Reducing volunteer bias: using left-over specimens to estimate rates of HIV infection among inmates in Ontario, Canada.

OBJECTIVE: To estimate the prevalence of HIV-1 infection among adult and young offenders admitted to remand facilities in the province of Ontario, Canada, by using a design that reduces volunteer bias. METHODS: A study using a modified anonymous HIV-surveillance design was conducted with urine specimens routinely collected from male and female entrants to all Ontario jails, detention and youth centres between February and August 1993. Information on sex, age, and history of injecting drug use was also collected. Urine was screened using a modified commercial HIV enzyme-linked immunosorbent assay kit and confirmed using a modified in-house Western blot assay. RESULTS: Data were obtained on 10,530 adult men, 1518 adult women, 1480 young male offenders, and 92 young female offenders. Urine specimens were available for 88% of new entrants. Of the entrants, 1% (n = 163) refused to have their urine used for research. Refusals were not associated with history of injecting drug use. Overall rates of HIV-1 infection were 1% for adult men, 1.2% for adult women, and 0% for young offenders. Both the rates of infection and prevalence of injecting drug use varied across facilities and geographic regions. Overall, 13% of adult men, 20% of adult women, 3% of young male offenders, and 2% of young female offenders reported a history of injecting drug use. Rates of infection were highest among self-reported injecting drug users. Rates of HIV were 3.6% for adult men and 4.2% for adult women who injected compared with 0.6 and 0.5%, respectively, for non-injecting drug users. CONCLUSIONS: The use of unlinked left-over specimens is an important tool for measuring HIV-prevalence rates and should be encouraged. The results indicate that HIV rates are much higher among those entering prisons than in the general population. The pattern of HIV in Ontario prisons is similar to that reported in Europe and the United States. We are optimistic that these data will stimulate much needed efforts towards education and health promotion, and open the door to further research in Canadian prisons.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Age-related decline in striatal dopamine transporter binding with iodine-123-beta-CITSPECT.

UNLABELLED: The effect of age on human striatal dopamine (DA) transporters was investigated with SPECT using the ligand [123I]2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([123I]beta-CIT). METHODS: Iodine-123-beta-CIT binding in the striatum was examined in 28 healthy human subjects (14 men, 14 women) who ranged in age from 18 to 83 yr. Following injection with [123I]beta-CIT (mean +/- s.d. = 9.9 +/- 1.2 mCi), subjects were scanned with the brain-dedicated CERASPECT camera. A reconstructed transaxial slice 13.3-mm thick at the level of maximal striatal activity was used to determine tracer uptake in striatal and occipital regions of interest. The stability of regional uptake on Day 2 (approximately 18-24 hr postinjection) permitted estimation of the specific-to-nondisplaceable equilibrium partition coefficient: V3", calculated as (striatal--occipital)/occipital uptake at equilibrium. RESULTS: Values of V3" ranged from 3.6 to 11.4 for this sample (6.7 +/- 1.9). V3" showed a significant inverse correlation with age (r = -0.73, n = 28, p < 0.0001). Linear regression analysis revealed that V3" declined by 51% over the age range studied or approximately 8% per decade. CONCLUSION: These findings confirm postmortem reports of dopamine transporter loss with aging. In vivo methodologies may permit the age-related degeneration of dopamine nerve terminals to be studied in relation to the cognitive and motor deficits that occur in normal aging.

Adolescent↗
PubMed1995

Effect of dexfenfluramine on body weight, blood pressure, insulin resistance and serum cholesterol in obese individuals.

The effect of the serotonergic agent dexfenfluramine on weight loss, blood pressure, insulin sensitivity and serum lipid levels was determined in a 3-month randomised, double-blind, placebo controlled parallel design study in 50 obese subjects (body mass index 30-44 kg/m2). When compared with placebo treated patients, the dexfenfluramine group lost more weight (3.8 vs 1.1 kg, P < 0.01), had lower diastolic blood pressure (-5 vs -1.5 mmHg, P < 0.05), and lower cholesterol levels (-0.38 vs + 0.06mmol/l, P < 0.05), and showed improved insulin sensitivity (+ 11% vs + 4%, P < 0.03). Significant effects on blood pressure and insulin sensitivity were apparent after 1 week of treatment during which time weight did not change, suggesting a direct effect of the agent independent of weight loss. Dexfenfluramine thus improves a number of cardiovascular risk factors associated with obesity, with benefits additional to those achieved by weight reduction alone.

Adult↗
PubMed1994

Graphical, kinetic, and equilibrium analyses of in vivo [123I] beta-CIT binding to dopamine transporters in healthy human subjects.

The in vivo kinetics of the dopamine (DA) transporter probe 123I-labeled 2 beta-carboxymethoxy-3 beta-(4-iodophenyl) tropane ([123I] beta-CIT) in striatum was investigated with single-photon emission computerized tomography (SPECT) in five healthy human subjects. The aim of this study was to derive an adequate measure of the DA transporter density that would not be affected by regional cerebral blood flow or peripheral clearance of the tracer. SPECT data were acquired on the day of injection (day 1) from 0 to 7 h and on the following day (day 2) from 19 to 25 h. Arterial sampling on day 1 was used to measure the input function. Graphical, kinetic, and equilibrium analyses were evaluated. Graphical analysis of day 1 data, with the assumption of negligible dissociation of the tracer-receptor complex (k4 = 0), was found to be blood flow-dependent. A three-compartment kinetic analysis of day 1 data were performed using a three (k4 = 0)- and a four (k4 > 0)-parameter model. The three-parameter model estimated the konBmax product at 0.886 +/- 0.087 min-1. The four-parameter model gave a binding potential (BP) of 476 ml g-1, a value consistent with in vitro measurements. The stability of the regional uptake on day 2 allowed direct measurement of the specific to nonspecific equilibrium partition coefficient (V3" = k3/k4 = 6.66 +/- 1.54). Results of day 1 kinetic analysis and day 2 equilibrium analysis were well correlated among subjects. Simulations indicated that the error associated with the day 2 equilibrium analysis was acceptable for plasma tracer terminal half-lives > 10 h. We propose the equilibrium analysis on day 2 as the method of choice for clinical studies since it does not require multiple scans or the measurement of the arterial plasma tracer concentrations.

Adult↗
PubMed1994

Sex hormones regulate ABR latency.

In an effort to characterize more completely the influence of sex hormones on auditory brainstem response (ABR) latency, we evaluated the ABRs of normal male and female subjects and women with previously diagnosed endocrinologic syndromes. We describe ABR latency results from the following subjects: five normal males, nine normally cycling females on no hormonal therapy, nine females using oral contraceptive pills, five females with premature ovarian failure (POF) undergoing cyclic estrogen-progesterone replacement therapy, and five hyperandrogenized females with polycystic ovarian disease (PCOD) treated with the gonadotropin-releasing hormone agonist, Lupron depot, to suppress ovarian steroid production. All subjects were between 23 and 40 years of age. Serum levels of estradiol, progesterone, testosterone, prolactic, and gonadotropins (lutienizing hormone and follicle stimulating hormone) were measured to document the hormonal status of each of the subjects at the time of the ABR evaluation. Normal cycling females and females with POF underwent ABR testing during different phases of the same cycle. Male subjects and females using birth control pills were studied four times in the same month at 1-week intervals. Females with PCOD were also studied four times; baseline and then at 2-week intervals after the initiation of Lupron depot therapy. Increased ABR wave V peak latencies were found to be associated with elevated levels of estrogen or testosterone. We have previously reported a lengthening of ABR wave V peak latencies coincident with peak estrogen levels during the female cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Whole-body biodistribution, radiation absorbed dose and brain SPECT imaging with iodine-123-beta-CIT in healthy human subjects.

UNLABELLED: SPECT imaging with 123I-labeled methyl 3 beta-(4-iodophenyl)tropane-2 beta-carboxylate ([123I]beta-CIT) in nonhuman primates has shown brain striatal activity, which primarily reflects binding to the dopamine transporter. The biodistribution and calculated radiation-absorbed doses of [123I]beta-CIT administered to eight healthy subjects were measured with attention to the accurate determination of organ time-activity data. METHODS: Whole-body transmission images were obtained with a scanning line source for attenuation correction of the emission images. Following administration of 92.5 +/- 22.2 MBq (2.5 +/- 0.6 mCi) of [123I]beta-CIT, subjects were imaged with a whole-body imager every 30 min for 3 hr, every 60 min for the next 3 hr and at 12, 24 and 48 hr postinjection. Regional body conjugate counts were converted to microcuries of activity, with a calibration factor determined in a separate experiment using a distributed source of 123I. RESULTS: The peak brain uptake represented 14% of the injected dose, with 2% of the activity approximately overlying the striatal region. Highest radiation-absorbed doses were to the lung (0.1 mGy/MBq, 0.38 rads/mCi), liver (0.087 mGy/MBq, 0.32 rads/mCi) and lower large intestine (0.053 mGy/MBq, 0.20 rads/mCi). CONCLUSIONS: Iodine-123-beta-CIT is a promising SPECT agent for imaging of the dopamine transporter in humans with favorable dosimetry and high brain uptake.

Adult↗
PubMed1993

Single photon emission computed tomographic imaging demonstrates loss of striatal dopamine transporters in Parkinson disease.

[123I][(1R)-2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane] ([123I]beta-CIT) labels dopamine transporters and is, therefore, a marker of neurons that degenerate in Parkinson disease. Single photon emission computed tomography imaging with [123I]beta-CIT showed that radioactivity in striatal regions in healthy subjects increased during a 2-day imaging study, whereas that in Parkinsonian patients peaked earlier at reduced levels relative to healthy subjects. Kinetic analyses of radioactivity in plasma and brain suggest that this decrease was due to an approximately 65% loss of target sites in patients compared with healthy subjects; greater losses occurred in putamen than in caudate. All patients showed lateralized differences in striatal uptake, with greater losses in the striatum contralateral to the side of the body with initial symptoms. These preliminary results suggest that [123I]beta-CIT is a marker for the loss of striatal dopamine terminals in patients with Parkinson disease. Single photon emission computed tomographic imaging with [123I]beta-CIT may be useful for early diagnosis of the disorder, for monitoring the progression of the disease, and for distinguishing the idiopathic disorder from other Parkinsonian syndromes with more widespread pathology.

Adult↗
PubMed1992

Cyclic steroid replacement alters auditory brainstem responses in young women with premature ovarian failure.

To determine the independent contributions of estradiol and progesterone to the auditory brainstem response (ABR) latency changes associated with the menstrual cycle, we obtained ABRs on young women with premature ovarian failure who were undergoing cyclic hormone replacement therapy (HRT). We evaluated the influence of cyclic HRT on the ABRs of young women in three controlled phases of the same replacement cycles: 1) no steroid replacement, 2) estrogen-only replacement (E2-only), and 3) estrogen-plus-progesterone replacement (E2-plus-P). A significantly lengthening of wave V peak latency and I-V interpeak interval was found during E2-only replacement. Despite equivalent circulating estradiol levels, both wave V peak latencies and wave I-V interpeak intervals significantly decreased during the E2-plus-P replacement phase as compared to the E2-only replacement phase. These findings are compatible with the hypothesis that estradiol potentiates secretion of the inhibitory neurotransmitter gamma-amino-butyric acid (GABA) at auditory nerve synapses, leading to delayed synaptic conduction time. Progesterone is known to blunt E2-potentiated GABA release and may antagonize its prolongation of wave V latency.

Adult↗
PubMed1992

The Ontario HIV seroprevalence study of childbearing women: results from the first year of testing.

The Ontario HIV Seroprevalence Study of Childbearing Women is an unliked anonymous seroprevalence study designed according to the well-established ethical and legal guidelines for such studies. Commencing in November, 1989, randomly selected neonatal heelprick specimens were tested for the presence of HIV antibodies after all identifying information had been permanently and irrevocably unlinked from the specimens. During the first year of the study 94,119 (approximately 60% of all submitted specimens) were tested. Twenty-six specimens which were repeatedly reactive by EIA were confirmed as positive for an overall crude seroprevalence rate of 2.8 per 10,000 women having live births (95% CI: 1.8-4.1). Twenty-five of the 26 confirmed seropositive results came from babies born in hospitals in the Metropolitan Toronto, Ottawa-Carlton, or Hamilton-Peel-Halton regions.

Adult↗