Biomedical subjects

A A Wright

Publications and source records attributed to A A Wright.

At least 19 recordsLinked to original sources

PubMed2005

Oral lesions as indicators of HIV infection among routine dental patients in Lagos, Nigeria.

OBJECTIVES: To document the incidental oral lesions of human immunodeficiency virus (HIV) infection, the pattern and frequency of the lesions based on clinical presentation and oral manifestations in routine dental patients who tested positive in Nigeria. SUBJECTS AND METHODS: The study was conducted at the Oral Diagnosis/Oral Medicine clinic of the Lagos University Teaching Hospital, Lagos, Nigeria between May 2002 and April 2003. During this period, all patients with oral lesions suggestive of HIV/acquired immunodeficiency syndrome (AIDS) as described in the EEC-WHO Classification and diagnostic criteria of oral lesions of HIV were counseled and offered voluntary HIV testing. All the 35 patients who consented and tested positive were included in this study. RESULTS: Of a total of 700 patients 53 patients with oral lesions suggestive of HIV/AIDS were seen, thirty-eight (72%) consented to HIV screening, 15 patients (28%) refused. Thirty-five patients (92%), mean age 36 +/- 13 years were confirmed positive for HIV. Oral candidiasis was the commonest lesion seen (43%) the second common being Herpes zoster (23%). Other lesions seen included erythema multiforme in two (6%), facial palsy in two (6%) and oral hairy leukoplakia in one (3%). CONCLUSION: An oral mucosal lesion may be the presenting lesion of HIV/AIDS in routine patients attending the dental clinic. Oral health care workers should practice optimal infection control based on the Centers for Disease Control 'Standard Precautions' guidelines on infection control for all patients to minimize occupational transmission of HIV.

Adolescent↗

PubMed2005

Facial neuralgias: analysis of the different types seen at Lagos University Teaching Hospital, (Luth).

OBJECTIVE: To highlight the presentations, characteristics. the difficulties in diagnosis, treatment and response to treatment types of facial neuralgias seen at Lagos University Teaching Hospital. METHODS: Twelve patients with facial neuralgias diagnosed and treated in dental clinic of the Lagos University Teaching Hospital were studies. Using strict for diagnosis, patients were categorized into: trigeminal, glosspharyngeal and post herpetic neuralgias. RESULTS: Eight patients had trigeminal neuralgia; three patients had post -herpetic neuralgia and one patient had glossopharyeal neuralgia. In six patients with Trigeminal neuralgia. mandibular branch was affected, while in the two patients maxillary branch was affected. Six patients with Trigeminal neuralgia responded to carbamazepine alone and 2 had additional drugs. The only patients with glosspharyngeal neuralgia responded to carbamazepine. One patient with post herpetic neuralgia tested positive for HIV. All the post herpetic neuralgia responded poorly to carbamezepine. CONCLUSION: Facial neuralgias are uncommon and usually present in the dental clinic. They can easily be misdiagnosed with resulting inappropriate. Correct diagnosis and treatment with carbamezepine is beneficial in majority of patients.

Adult↗

PubMed2005

Group II and III lesions in HIV positive Nigerians attending the General Hospital Lagos, Nigeria.

OBJECTIVE: To document the prevalence of Group II and Ill oral lesions of HIV in adult seropositive Nigerians. STUDY DESIGN: A longitudinal study of 100 HIV infected adult Nigerian patients attending the HIV Clinic of the General Hospital, Lagos, Nigeria. STUDY PERIOD: January 2001 to October 2002. METHOD: Oral lesions were diagnosed based on documented diagnostic criteria by GREENSPAN et al, for oral manifestation of HIV. WHO classification of oral lesions based on the degree of association with HIV infection was also used. Oral lesions were treated using established treatment protocols. RESULTS: Seventy patients had oral lesions of HIV, of these fourteen (20%) patients had Group II and III oral lesions of HIV infection: Five (7%) patients had recurrent aphthous ulcers (RAU), 4 (6%) had herpes zoster of the trigeminal nerve. Majority of patients presented with oral symptoms severe enough to require use of appropriate medication. Recurrence of oral lesions occurred in all cases of RAU seen. CONCLUSION: Group II and III lesions are less prevalent than group I lesions in HIV infected adult Nigerians. They may be the presenting oral lesions of HIV/AIDS. These oral lesions of HIV are associated with a lot of pain, morbidity and may also compromise aesthetics. By compromising adequate nutrition and practice of good oral hygiene, they may lead to further deterioration of the health of the patient and can accelerate the course of the disease. Early recognition and diagnosis of these lesions by the oral clinician and/or trained dental practitioner affords the patient the opportunity of receiving prompt and appropriate medical treatment as well as counseling.

Adolescent↗

PubMed2004

Improving the implementation of community-acquired pneumonia guidelines.

Best practice guidelines define the essential elements of care. They can improve the treatment of patients with community-acquired pneumonia (CAP). Although guidelines advocating these elements are readily avail-able, the care received by patients with CAP remains heterogeneous. In the present report, the use of a -computer-based assistant to decision-making was -successfully developed and tested, improving the application of well-known guidelines.

Community-Acquired Infections↗

PubMed2000

Music perception and octave generalization in rhesus monkeys.

Two rhesus monkeys were tested for octave generalization in 8 experiments by transposing 6- and 7-note musical passages by an octave and requiring same or different judgments. The monkeys showed no octave generalization to random-synthetic melodies, atonal melodies, or individual notes. They did show complete octave generalization to childhood songs (e.g., "Happy Birthday") and tonal melodies (from a tonality algorithm). Octave generalization was equally strong for 2-octave transpositions but not for 0.5- or 1.5-octave transpositions of childhood songs. These results combine to show that tonal melodies form musical gestalts for monkeys, as they do for humans, and retain their identity when transposed with whole octaves so that chroma (key) is preserved. This conclusion implicates similar transduction, storage, processing, and relational memory of musical passages in monkeys and humans and has implications for nature-nurture origins of music perception.

Analysis of Variance↗

PubMed1999

Visual list memory in capuchin monkeys (Cebus apella).

Memory of 3 capuchin monkeys, Cebus apella, was tested with lists of 4 travel-slide pictures and different retention intervals. They touched different areas of a video monitor to indicate whether a test picture was in a list. At short retention intervals (0 s, 1 s, 2 s), memory was good for the last list items (recency effect). At a 10-s retention interval, memory improved for 1st list items (primacy effect). At long retention intervals (20 s and 30 s), primacy effects were strong and recency effects had dissipated. The pattern of retention-interval changes was similar to rhesus monkeys, humans, and pigeons. The time course of recency dissipation was similar to rhesus monkeys. The capuchin's superior tool-use ability was discussed in relation to whether it reflects a superior general cognitive ability, such as memory. In terms of visual memory, capuchin monkeys were not shown to be superior to rhesus monkeys.

Animals↗

PubMed1999

Auditory list memory and interference processes in monkeys.

Memory of 2 rhesus monkeys (Macaca mulatta) was tested in a serial probe recognition task with lists of 4 natural or environmental sounds, different retention intervals, and different manipulations of interference. At short retention intervals, increasing the separation of list items reduced the primacy effect and produced a recency effect. Similar results were shown by increasing interference across lists through item repetitions or making the first 2 list items high-interference items. These results indicated that decreasing first-item performance reduced proactive interference on memory of the last list items. At long (20 s) retention intervals, making the last list items of high interference reduced the recency effect, reduced retroactive interference, and produced a primacy effect. Taken together, interference plays a role in determining the primacy and recency effects of the serial-position function.

Animals↗

PubMed1997

Memory of auditory lists by rhesus monkeys (Macaca mulatta).

Monkey auditory memory was tested with increasing list lengths of 4, 6, 8, and 10 sounds. Five-hundred and twenty environmental sounds of 3-s duration were used. In Experiment 1, the monkeys initiated each list by touching the center speaker. They touched 1 of 2 side speakers to indicate whether a single test sound (presented from both side speakers simultaneously) was or was not in the list. The serial-position functions showed prominent primacy effects (good first-item memory) and recency effects (good last-item memory). Experiment 2 repeated the procedure without the list-initiation response and with a variable intertrial interval. The results of both experiments were similar and are discussed in relation to theories and hypotheses of serial-position effects.

Animals↗

PubMed1994

Monkeys (Macaca mulatta) learn category matching in a nonidentical same-different task.

Same-different judgments of familiar objects and animals were investigated in rhesus monkeys (Macaca mulatta) in a task based on category matches rather than identity matches. Eighteen categories of familiar animals and objects were each composed of 12 color slides and were presented as pairs of slides. Ss indicated "same" or "different" on a response lever for reinforcement. On Same trials, 2 different views of the same object were presented, typically with differences in perspective, lighting, and background. On Different trials, 2 pictures of different objects were presented. Ss acquired the category discriminations and transferred their response judgments accurately to novel pictures from the categories. Transfer was better to objects with which the monkeys had actually interacted rather than those with which they did not interact.

Animals↗

PubMed1994

Scratch and match: pigeons learn matching and oddity with gravel stimuli.

Two groups of 4 pigeons learned either matching-to-sample or oddity-from-sample by digging in white and black gravel for buried grain. Learning occurred as early as Trial 11, and acquisition was accelerated by as much as 100-fold compared with learning in traditional key-peck environments. Control experiments showed that performance was not controlled by cues other than the gravel stimuli and was not due to distributed practice effects of 8 trials per day and longer intertrial intervals.

Animals↗

PubMed1992

Learning mechanisms in matching to sample.

A model system and an experiment on early learning and decision processes in matching-to-sample and oddity-from-sample tasks are presented. The model system is based, in part, on videotaped records of pigeons' looking responses before they chose 1 of 2 comparison stimuli. In order to see the wavelength stimuli recessed behind the pecking keys, the pigeons had to move in front of them. Although there were slight increases in the acceptance probability with switches between the stimuli before a choice response, the overall decision strategy was close to a Markov choice process in which choice proportions could be predicted by the product of each rejection probability and the final acceptance probability. Learning involved learning to discriminate rather than learning to adopt a stricter criterion for an acceptable sample match.

Animals↗

PubMed1992

Concept learning by monkeys with video picture images and a touch screen.

Two rhesus monkeys were trained in a same/different task to discriminate digitized computer-stored picture stimuli. The pictures were digitized from 35-mm slides and presented in pairs on a computer monitor. The monkeys were required to touch the pictures and then make a choice response to indicate whether the pictures were identical or nonidentical. The response areas and stimuli were located to the sides of the picture stimuli. Responses were defined and monitored by an infrared matrix touch screen. After learning the same/different task, both monkeys showed performance accuracy with novel picture stimuli similar to that with training picture stimuli. This accurate novel-picture transfer indicates that a same/different concept had been learned, a concept similar to the one they had previously demonstrated in a different apparatus with rear-projected slide stimuli and a response lever.

Animals↗

PubMed1991

Color vision following intense green light exposure: data and a model.

Hue discrimination, spectral sensitivity, and mathematical models of both are presented for a rhesus monkey which was exposed to intense green light. One of the monkey's eyes was blue-blinded in a previous experimental procedure and the other was color normal. The results of green light exposure showed a loss of sensitivity on both measures, with greater loss in the blue-blinded eye. Although there was considerable loss of hue-discrimination in the blue-green spectral regions, hue-discrimination at the point of best discrimination, 590 nm, remained unaffected. This pattern of results poses difficulties for models of hue discrimination, and has resulted in the proposed model employing three opponent color channels. The number of free-parameters are minimized and the integration between spectral sensitivity and hue discrimination enhanced by deriving parameters used in modeling hue discrimination from spectral sensitivity or vice versa.

Animals↗

PubMed1990

Naming, rehearsal, and interstimulus interval effects in memory processing.

Recognition memory was tested for lists of 6 briefly (0.08 s) presented pictures at different interstimulus intervals (ISI) of 0.08, 1, and 4 s. Experiment 1 showed a 16% performance increase (ISI effect) for increasing ISI for travel slide but not kaleidoscope pictures. Experiment 2 showed that learning names for the kaleidoscope pictures then resulted in a substantial (20%) ISI effect, not attributable solely to the added exposure to the pictures. Experiment 3 required names, color evaluations, or blank stares during list-memory presentations. Interviews established that the most effective memory strategy was chaining the names together, followed by repeating the most current name, and in turn followed by reliance upon only the sensory experience. All groups in Experiments 2 and 3, independent of ISI effects, showed U-shaped serial position functions. Rehearsal is shown to be nonessential and cannot be the general cause of the primary effect of the serial position function.

Adolescent↗

PubMed1989

Relational and absolute stimulus learning by monkeys in a memory task.

Three experiments showed stimulus control by either the absolute properties of probe stimuli, relational properties of the probe-list relationship, or both in a serial probe recognition memory task in which a four-item memory list was followed by a single probe (test) item. In Experiment 1, 3 rhesus monkeys received 39 to 75 repetitions of the same 24-trial stimulus sequence. Special tests showed stimulus control by the absolute properties of the probe stimuli. Retention of previous relational control was demonstrated by the good transfer (83%) to novel list and probe stimuli at the beginning of Experiment 2. During Experiment 2, control by absolute properties of the probe stimuli gradually reoccurred. Only a small measure of control by list stimuli could be detected or promoted. In Experiment 3, 4 monkeys were shown to have largely lost their ability to perform on the basis of the list-probe relationship, and were performing primarily on the basis of the absolute properties of the probe stimuli. Over the next 15 weeks, these monkeys were transferred to new stimuli at the beginning of each week. Control by the relational aspects of the task gradually returned. As transfer performance increased, control by the absolute properties of the probe stimuli was eliminated. The results are discussed in terms of stimulus control and performance strategies used by the monkeys.

Animals↗

PubMed1989

Buildup and release from proactive interference in a rhesus monkey.

The potential of the buildup and release from proactive interference (PI) technique in the study of animal categorization was demonstrated with a rhesus monkey. A serial probe recognition task was used with a list of 4 consecutive slide pictures (upper screen) followed by a single probe picture (lower screen). The monkey moved a lever to indicate whether or not the probe was contained in the list. PI built over 40 consecutive trials tested with either flowers or primate faces. PI was released on category change and then built during 40 trials with the second category. The first 2 serial positions showed somewhat greater PI buildup and release, supporting conclusions from human studies that the effects occur primarily in secondary memory. A second experiment provided 2 replications of the main effect and showed through color border changes and elimination of color differences that color was not a critical feature.

Animals↗

PubMed1988

Long-term proactive interference and novelty enhancement effect in monkey list memory.

Serial-probe-recognition (SPR) performance by 2 monkeys deteriorated over several months of training. Three hundred and twenty different items were presented without repetition within a session (trial unique) but were repeated between sessions. The cause of the deterioration was identified as proactive interference (PI) due to repetitive use of items from day to day. Introduction of novel stimuli across days improved performance from 63% to 82% correct (Experiment 1). Tests with only probe items and no list items (Experiment 2) revealed that the monkeys were using a familiar/novel response strategy in combination with a relational strategy (relating the probe item to the list items) to further improve their SPR performance. Intermixing familiar baseline trials and novel transfer trials within a session (Experiment 3) encouraged the subjects to use a relational strategy, and it improved performance on baseline trials as well as on transfer trials. Possible qualitative similarity between the relational strategy and the familiar/novel response strategy is discussed along with theoretical implications of these findings for experiments which have used small number of repeating stimuli within a session.

Animals↗

PubMed1987

Researches on a unilaterally blue-blinded rhesus monkey.

Psychophysical measures of hue (wavelength) discrimination and spectral sensitivity were collected over a 3-year-period on a rhesus monkey whose right eye had been exposed to intense blue light 10 years prior and had shown a pronounced loss of blue sensitivity in an increment-threshold, spectral-sensitivity task. Hue discrimination, to a somewhat greater degree than spectral sensitivity, revealed large differences between the normal and blue-exposed eye. The difference limens were in some cases 100 nm for the blue-exposed eye compared to 10-15 nm for the normal eye. The hue-discrimination functions from the blue-exposed eye were similar in form to those from human tritanopes (blue-blind humans), and those from the monkey's normal eye were similar to those from normal humans. Detailed functions, where the variable wavelength was shorter as opposed to longer than the reference wavelength, were shown separately for each of the monkey's eyes; those from the blue-exposed eye were very similar to analogous functions from the one case where they have been shown separately for a human tritanope.

Animals↗