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Biomedical subjects

W C Duncan

Publications and source records attributed to W C Duncan.

At least 55 records · Page 3Linked to original sources
PubMed1985

Sleep and circadian rhythms in affective patients isolated from external time cues.

Sleep electroencephalographic activity, circadian rhythms in motor activity and rectal temperature, and clinical state were monitored longitudinally in four affectively ill patients (two depressed, one manic, and one rapidly cycling between depression and mania) who lived in isolation from external time cues (zeitgebers) for 3 to 4 weeks. In these conditions it was possible to observe the intrinsic or free-running behavior of circadian pacemakers and thereby to test several hypotheses about the role of sleep and circadian rhythms in the pathogenesis of depression. No hypothesis was consistently supported by the results. We found that the intrinsic rhythm of a circadian pacemaker appeared to free-run with an abnormally fast frequency in one patient. No patient remained stably depressed during temporal isolation. Our experience suggests that this type of study can be carried out safely with appropriate precautions. Temporal isolation is a means to test decisively predictions of several chronobiological hypotheses about affective illness and should be applied to additional patients.

Adult↗
PubMed1984

Chromomycosis. The association of fungal elements and wood splinters.

In two separate specimens received for histopathologic examination, pigmented fungal elements were found within or on embedded wood splinters associated with a foreign-body reaction. The fungus was found to be in direct contact with the surrounding dermis. These findings support the concept of inoculation as a pathogenetic mechanism in cutaneous chromomycosis.

Aged↗
PubMed1982

Antiplatelet therapy in atrophie blanche and livedo vasculitis.

Seven patients with atrophie blanche or livedo vasculitis of the lower extremities showed abnormal platelet functions in vitro. Six of seven showed hyperaggregation with epinephrine and/or collagen, three showed increased platelet adhesiveness, three showed increased platelet count, and one showed increased microemboli. After treatment with dipyridamole and aspirin, all showed return to normal platelet function. Clinical improvement occurred in all patients, with significant alleviation of pain and decrease in new lesion formation. Although enhanced healing of lesions seemed evident to physician and patient, it was incomplete. In two patients, pain returned when dipyridamole and aspirin were stopped, but the patients improved again when the medicines were restarted. These preliminary findings indicate a possible beneficial effect of antiplatelet therapy in atrophie blanche and livedo vasculitis. A double-blind study is being undertaken to further study this effect.

Adult↗
PubMed1982

Studies on the pathogenesis of the Jarisch-Herxheimer reaction: development of an animal model and evidence against a role for classical endotoxin.

The etiology of the Jarisch-Herxheimer reaction is unknown, but the reaction may result from toxic products of dead or dying treponemes reacting with sensitized syphilitic tissues. Because of similarities of spirochetes with gram-negative bacteria, endotoxin has been proposed as the responsible toxin. In 19 patients with syphilis, a reaction occurred in 15 (79%) during treatment with penicillin. Endotoxemia was not found by the limulus amoebocyte lysate test. All animal model of the Jarisch-Herxheimer reaction was developed in rabbits infected with Treponema pallidum. When treated with penicillin, 18 (78%) of 23 rabbits infected 18-29 days previously developed a reaction that resembled that in humans. Endotoxemia was not detected by the lysate test. After the reaction, rabbits were not refractory to the pyrogenic effects of endotoxin, and syphilitic rabbits rendered tolerant to endotoxin still developed fever when treated with penicillin. These data suggest that classical endotoxin is not the cause of the Jarisch-Herxheimer reaction.

Adult↗
PubMed1982

Topographic cortical mapping of EEG sleep stages during daytime naps in normal subjects.

Computer-generated cortical maps of power spectral estimates derived from 16 leads were drawn based on daytime sleep recordings in four normal volunteers. These data were compiled from nine 10-s artifact-free, EEG epochs from awake, stages 1-4 and REM sleep in each volunteer. EEG leads were placed on the left hemisphere and midline according to the 10-20 system with four additional interpolated posterior locations. Magnitude spectral estimates with 1 Hz resolution and adjacent frequencies (delta 2-4, alpha 8-12, beta 13-18) were analyzed with two-way ANOVA (lead by sleep stage). Delta activity was relatively uniform and of low amplitude in awake, eyes-closed subjects, and REM. Delta power increased at the vertex in stage 1. With progressing, non-REM sleep stages, it increased in power and enlarged radially to the intraparietal sulcus posteriorly, and the superior frontal gyrus anteriorly. Comparison of maps with ear and a computed average reference yielded similar topographic patterns. Alpha activity was expectedly maximal occipitally in awake subjects, but surprisingly a frontal area appeared in slow wave sleep. Beta activity in awake subjects was low and maximal parietally; stages 1 and REM showed even lower and more uniform distribution. Stage 2 showed the greatest power, concentrated at the vertex, with stages 3 and 4 diminishing. These data suggest that sleep stages are not completely uniform electrophysiologically across the cortex. This opens the possibility for a new method for the diagnosis of sleep disorders and alternatives in sleep staging.

Adult↗
PubMed1981

Age-related changes in sleep in depressed and normal subjects.

All-night electroencephalographic (EEG) sleep data were examined a function of age in normal control subjects and hospitalized, unmedicated depressed patients with primary affective illness. By analysis of variance, Total Sleep time, Delta Sleep, Sleep Efficiency, Rapid Eye Movement (REM) Sleep, and REM Latency decreased as a function of age, whereas Early Morning Awake time and Intermittent Awake time increased. Compared with normal controls, after the effects of age were covaried out, depressed patients had a greater Sleep Latency, Early Morning Awake time, Intermittent Awake time, Duration and REM Density of the first REM period, and average REM Density for the night, as well as less Sleep Efficiency, less Delta Sleep, and shorter REM Latency, Early Morning Awake time increased with age in depressives but not in normals.

Adolescent↗
PubMed1980

Bacterial interference of Neisseria gonorrhoeae by alpha-haemolytic streptococci.

Fifty pharyngeal isolates of alpha-haemolytic streptococci were tested against 20 cervical isolates of Neisseria gonorrhoeae for bacterial interference in vitro using the lawn-spotting method. Forty-seven (94%) isolates of streptococci showed inhibitory activity toward N gonorrhoeae, although nine of these were inhibitory to only one isolate of N gonorrhoeae. Isolates of N gonorrhoeae varied widely in their sensitivity to streptococci; the most sensitive were inhibited by 40 isolates of streptococci and the least sensitive by only 14 isolates. Species of Streptococcus found to inhibit growth of N gonorrhoeae were S mitis, S MG intermedius, S sanguis II, S mutans, and S morbillorum.

Adult↗
PubMed1980

Comparison between undecylenic acid and tolnaftate in the treatment of tinea pedis.

A double-blind parallel study comparing tolnaftate cream with undecylenic acid ointment and a placebo ointment in the treatment of symptomatic tinea pedis was conducted on the warm, humid Texas Gulf Coast. In one hundred and three patients studied, both the clinical and mycological effects of the two antifungal agents were indistinguishable. Both were significantly more effective than the placebo.

Clinical Trials as Topic↗
PubMed1980

Relationship between EEG sleep patterns and clinical improvement in depressed patients treated with sleep deprivation.

The effects of a single night of total sleep deprivation were observed in 16 primary depressed patients. Responders to treatment were rated as significantly more depressed and revealed a more "depressed" EEG sleep pattern prior to sleep deprivation than did nonresponders. Following sleep deprivation, patients who improved experienced a rebound in REM sleep during the second night of recovery sleep.

Adult↗
PubMed1979

Muscarinic supersensitivity: a possible model for the sleep disturbance of primary depression?

The sleep changes induced in normal volunteers following the administration of scopolamine on 3 consecutive mornings resemble many of the abnormalities observed in the sleep of patients with primary depression: increased sleep latency and reduced rapid eye movement (REM) latency, total sleep time, and sleep efficiency. Furthermore, in a multivariate discriminant analysis--previously shown to distinguish the sleep records of depresed patients from those of normal controls and insomniac patients--the records from baseline nights were selected as normal and those after scopolamine as predominately depressed. Those observations suggest to us that muscarinic supersensitivity in normals may function as a pharmacological model for the sleep disturbances of depression.

Depression↗
PubMed1979

REM architecture changes in bipolar and unipolar depression.

The authors compared total night sleep measures and REM sleep architecture values for normal control subjects (N = 36), unipolar depressed patients (N = 36), and bipolar depressed patients (N = 22). The unipolar and bipolar patients had significantly greater fragmentation of REM periods than control subjects, and bipolar patients showed greater fragmentation of REM periods than unipolar patients. In both the unipolar and bipolar samples, the duration of successive REM periods was related to the total number of REM periods during sleep.

Bipolar Disorder↗
PubMed1979

Hypopigmentation in alopecia mucinosa.

Alopecia mucinosa was found in the hypopigmented skin of two black patients. Alopecia mucinosa should be included in the differential diagnosis of hypopigmented papular skin lesions.

Alopecia↗
PubMed1978

Method for studying the role of indigenous cervical flora in colonisation by Neisseria gonorrhoeae.

A method for quantitating cervical flora has been evaluated statistically and used to study the bacterial flora of the cervix in 14 women sexually exposed to men with gonococcal urethritis. A comparison was made between those women who subsequently became colonised with Neisseria gonorrhoeae and those who did not to determine whether either total microbial populations or the different species present could be related to colonisation by N. gonorrhoeae. Two control groups of healthy women, one of patients from a public clinic and the other of patients from a private practice, were studied in the same way. Normal flora isolates were tested in vitro for antagonism or synergism toward N. gonorrhoeae or both. Cervical flora was characterised in all patient groups by wide variations between individuals, both in type and numbers of organisms. No significant differences were found in total bacterial populations or in the number of species isolated from the cervix between patient groups. Populations of N. gonorrhoeae ranged from less than 10 bacteria to log104.36. Only one normal flora isolate, a strain of Streptococcus viridans isolated from a woman exposed to but not infected by N. gonorrhoeae, demonstrated inhibition of growth towards N. gonorrhoeae.

Bacteriological Techniques↗