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Biomedical subjects

W Houston

Publications and source records attributed to W Houston.

16 recordsLinked to original sources
PubMed2003

A multicenter, randomized, placebo controlled, multiple-dose, safety and pharmacokinetic study of AIT-082 (Neotrofin) in mild Alzheimer's disease patients.

A phase 1, randomized, double-blind, placebo-controlled, dose escalation study of the purine derivative, AIT-082 (Neotrofin, NeoTherapeutics) was conducted in mild Alzheimer's disease (AD) patients to evaluate multiple-dose safety, tolerability, and pharmacokinetics. Possible short-term effects of AIT-082 on cognition and memory were preliminarily investigated. AIT-082 is currently being developed as a potential treatment for Alzheimer's disease and other neurological disorders. Pre-clinical studies indicate that AIT-082 has memory enhancing properties, stimulates neuritogenesis and the production of neurotrophic factors. Patients received an oral dose of AIT-082 or placebo daily for one week. Thirty-six AD patients were divided into three dose cohorts; each dose cohort consisted of twelve patients with 8 patients randomized to AIT-082 and 4 to placebo. The 3 doses of AIT-082 evaluated in this study were 100 mg/day, 500 mg/day, and 2,000 mg/day. There were no serious adverse events at any dose and the drug was well tolerated without significant side effects. AIT-082 was orally and rapidly absorbed, resulting in peak serum concentrations within 2 hours with an elimination half-life of approximately 20 hours. Higher doses resulted in corresponding increases in peak concentrations and areas under the curve (AUC). There was an approximate 2-fold accumulation in AIT-082 with daily dosing (as reflected by the AUC) at steady state. There were no significant differences by treatment arm on the clinical or neuropsychological evaluations. AIT-082 was rapidly absorbed by the oral route with a half-life suitable for dosing once or twice daily. No problems with tolerability or safety were found. AIT-082 appears suitable for testing in larger clinical trials for the treatment of AD and other neurologic disorders.

Administration, Oral↗
PubMed1996

Preserved color imagery in an achromatopsic.

The loss of color vision secondary to central nervous system disease (achromatopsia) is thought to preclude visual imagery of colors. We report a patient with achromatopsia, secondary to bilateral temporo-occipital infarcts inclusive of the lingual and fusiform gyri, with preserved color imagery. Our findings, in conjunction with previous cases in the literature, are consistent with a single neural network for color processing in which a disconnection of internal activation from stored color representations produces impaired color imagery with preserved color perception, whereas a disconnection of visual input to these representations produces achromatopsia with preserved color imagery.

Cerebral Infarction↗
PubMed1996

The differential effects of simulating malingering, closed head injury, and other CNS pathology on the Wisconsin Card Sorting Test: support for the "pattern of performance" hypothesis.

We investigated the effects of faking bad on the Wisconsin Card Sorting Test, comparing the performance of simulating malingerers (M; n = 24) to controls (C; n = 21), closed head-injured patients (CHI, n = 70), and patients with mixed CNS pathology other than CHI alone (CNS; n = 89). Stepwise discriminant functions achieved good accuracy (91-96%), sensitivity (58-100%), and specificity (92-100%) in differentiating simulating malingerers from these groups. The Categories score was a consistent significant independent discriminating variable. Categories alone could differentiate between the M and C groups. However, in discriminating between simulating malingerers and both CHI or CNS patients, more complex patterns of performance emerged, consisting of relatively poorer performance ratios on Categories compared to Perseverative Errors. This supported the Pattern of Performance theory of the effects of simulating malingering on neuropsychological tests, which holds that people simulating malingering do more poorly on obvious vs. subtle tasks compared to people with verified brain damage. Due to the difficulty of tracking one's performance on several different indices simultaneously, known patterns of performance for patients with verified brain dysfunction should be very difficult to fake, even with coaching.

Journal Article↗
PubMed1995

Repetition and the arcuate fasciculus.

According to the traditional model of language organization, repetition deficits arise following damage to the arcuate fasciculus of the dominant hemisphere (conduction aphasia). Conduction aphasia may result from lesions that spare the arcuate fasciculus. However, these patients have atypical language organization. We describe a man with normal language architecture who underwent a resection of the anterior portion of his arcuate fasciculus and retained his ability to repeat words and sentences. We propose that the arcuate fasciculus is not necessary for speech repetition by the lexical route.

Adult↗
PubMed1993

Malingering on neuropsychological memory tests: potential objective indicators.

We evaluated five potential indicators of malingering on the Rey Memory Test (RMT), Hebb's Recurring Digits (HRD), the Wechsler Memory Scale-Revised (WMS-R), the Complex Figure Test (CFT), and the Auditory Verbal Learning Test (AVLT). Fifty-seven subjects were assigned randomly to either a control group or a simulated malingering group. Two indicators-discriminant functions derived from the WMS-R and from the CFT/AVLT-achieved classification accuracy of 88% and 86%, respectively, without misidentifying controls as malingerers. Among the remaining indicators, there were problems with the recommended RMT cut-off, but it and the HRD show some promise. Subjects who simulated malingering did so by suppressing performance on tasks that involve recall as well as recognition memory and are relatively easy, but not obviously so.

Adult↗
PubMed1993

Discriminating between simulated malingering and closed head injury on the Wechsler Memory Scale-Revised.

We tested the hypothesis that malingering is distinguished by poorer performance on recognition relative to recall tasks by evaluating the ability of discriminant functions to distinguish between 89 subjects simulating malingering and 44 subjects with a history of closed head injury (CHI) on the Wechsler Memory Scale - Revised (WMS-R). Functions with good accuracy in discriminating between simulated malingerers and controls in prior studies did not have adequate specificity when applied to the CHI group. A newly derived discriminant function achieved overall classification accuracy of 79% for the malingering versus CHI groups on cross-validation, with 79% sensitivity (true positives for malingering) and 80% specificity (true negatives for closed head injured). A complex performance pattern on seven WMS-R subtests distinguished malingering subjects from those with CHI, but did not support the recognition versus recall hypothesis. The malingering pattern involved: (a) power performance on two relatively (but inconspicuously) easy tasks dependent on immediate recall (Visual Reproduction I and Visual Memory Span); (b) better performance on two relatively (but inconspicuously) easy tasks dependent on immediate recall (Visual Paired Associates I and Digit Span); (c) poorer performance on two relatively difficult delayed tasks (Logical Memory II and Visual Paired Associates II); and (d) better performance on another difficult task involving delayed recall (Visual Reproduction II).

Journal Article↗
PubMed1975

Kaposi's sarcoma of the penis.

The 11th case of Kaposi's sarcoma of the glans penis is reported. Aetiology and treatment are discussed and evidence adduced to support a conservative surgical approach by local excision, supplemented if necessary by low dosage irradiation and possibly methotrexate infusion.

Adult↗
PubMed1965

Intersex in an infant.

Explore the source record for details and available documents.

Disorders of Sex Development↗