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Biomedical subjects

W S Cain

Publications and source records attributed to W S Cain.

At least 73 records · Page 4Linked to original sources
PubMed1986

Odor perception in temporal lobe epilepsy patients with and without temporal lobectomy.

The investigation employed monorhinic (single nostril) olfactory testing to decide whether patients with unilateral anterior temporal lobe resection (N = 16) and patients with unoperated temporal lobe epilepsy (N = 18) have impaired ability to detect, remember, and identify odors. A shape memory task accompanied the odor memory task for comparison. The lobectomy patients showed a minor bilateral depression of absolute sensitivity but still fell within the clinically normal range. The lobectomy patients showed impairment of odor recognition memory but strictly via the nostril ipsilateral to the resected lobe. A similar ipsilateral-contralateral asymmetry characterized the performance of these patients in odor identification. In that case, however, performance via the contralateral nostril showed some impairment too. Nonsurgery patients also exhibited some impairment in odor identification, but bilaterally. Finally, both groups of patients fell somewhat below normals in recognition memory for amorphous shapes. The various results implied that temporal lobe epilepsy alone takes some toll on olfactory information processing and that temporal lobe resection exacerbates the problem, but only on the side of surgery.

Adult↗
PubMed1986

Aging and the perception of nasal irritation.

Three types of measurement were employed to assess the effects of aging on nasal irritation (common chemical sense). These were measurement of detection threshold of CO2 mixed with air, measurement of the threshold concentration of CO2 that causes a transient reflex apnea, and measurement of the suprathreshold perceived strength of five levels of CO2 by the method of magnitude matching. Ancillary measurements included nasal airflow resistance and magnitude matching of an odorant (1-butanol). Twenty elderly (67 to 93) and twenty young persons (19 to 31) served as subjects. The young and elderly gave no evidence of average difference in detection threshold. In contrast, the elderly group showed a strong elevation of the threshold of apnea and a marked weakening of perceived CO2 suprathreshold strength. CO2 and butanol approximated power functions of concentration level, functions for the elderly being depressed relative to those for the young. Although the elderly had on the average slightly higher nasal resistance than the young, the differences played at most a minor role in the perception of nasal stimuli.

1-Butanol↗
PubMed1986

Odor identification: the blind are better.

Twenty sighted and twenty blind adults, 19 to 66 years of age, participated in tests of olfactory sensitivity to n-butyl alcohol and of identification of 80 everyday odors. The blind had poorer absolute sensitivity, but outperformed the sighted at identification. Age proved an important factor in the comparison; more than half the variance in identification within each group was ascribable to an age-related decline.

Adult↗
PubMed1985

Respiratory symptoms associated with sulfur dioxide exposure.

Exposures to sulfur dioxide (SO2) have been associated with progressive, dose-dependent bronchoconstriction in sensitive individuals. The clinical significance of such changes remains poorly characterized. We studied subjective responses following exposure to low level concentrations of SO2 (less than 1 ppm) in a group of 10 healthy and 10 asthmatic subjects. The number and severity of complaints associated with SO2 increased with concentrations in both healthy and asthmatic subjects. Asthmatics indicated progressive lower respiratory complaints, such as wheezing, chest tightness, dyspnea and cough with increasing levels of SO2 while healthy subjects complained more frequently of upper airway complaints such as taste and odor with increasing levels of SO2. Exercise increased the frequency of lower airway symptoms in asthmatics but led to no increases in symptoms in healthy subjects.

Adult↗
PubMed1985

Smell of danger: an analysis of LP-gas odorization.

LP-gas derives warning properties from the odorants ethyl mercaptan or thiophane. Laboratory tests have implied that the average person has the ability to smell the odors before leaking LP-gas reaches one-fifth its lower limit of flammability. Generally, however, laboratory tests ignore or discard persons with a poor sense of smell, especially the elderly and persons with certain types of hyposmia. Some persons who apparently can smell the warning agents when directed may otherwise fail to notice or identify them. Elderly men seem particularly vulnerable to instances of incidental anosmia and olfactory agnosia. Psychophysical testing of the warning agents has been rather unsophisticated. There exists neither a standard protocol for testing nor adequate specification of the perceptual properties that might make one warning agent better than another. Without such developments, improvement in warning agents will fail to occur. Possible improvements include increases in concentration, the use of blends to insure more uniform delivery of agent and, to decrease the perceptual vulnerability of relatively insensitive people, use of agents with favorable psychophysical (stimulus-response) functions and use of agents with favorable adaptation characteristics. Even without a change in existing products, it seems advisable to learn more about the vulnerability of LP-gas users and to employ educational means to reduce risks.

Diffusion↗
PubMed1985

Stability of tobacco smoke odor in enclosed spaces.

During each of five experiments, four sedentary subjects smoked a total of 8 cigarettes during one hour while occupying an odor test chamber. The air temperature was 20-22 degrees C and the relative humidity was 35-50%. During the entire test period (6 h) the odor intensity in the chamber was evaluated by judges. After smoking ceased, the odor intensity continued to rise for one or two hours and then remained constant in a way that is characteristic of unreactive contaminants.

Climate↗
PubMed1984

Childhood liposarcoma. Report of a case and review of the literature.

A case of liposarcoma presenting in an adolescent black male is described. Features unique to this case include a mediastinal primary site (the fourth to be documented in a pediatric patient), a demonstrable response to radiotherapy and chemotherapy allowing complete surgical excision of an initially inoperable tumor, and the apparent histologic maturation of the tumor following multimodal therapy. A review of previously published accounts of pediatric liposarcoma revealed the following: (1) peak incidences during infancy and in early adolescence; (2) the extremities to be the most common site of origin (51%); (3) a predominance of myxoid histology (76%); and (4) a lower overall recurrence rate when compared with adult cases (37% versus 72%, respectively). The influence of histology, location of the tumor, and completeness of surgical excision on the prognosis of adult liposarcoma was confirmed in this limited pediatric experience. While the use of radiotherapy and chemotherapy cannot be advocated in all instances of liposarcoma, our experience and that from other reports would support the incorporation of these modalities of treatment in selected patients where the tumor is surgically inaccessible due to size.

Adolescent↗
PubMed1984

Odor recognition: familiarity, identifiability, and encoding consistency.

The investigation examined the association between the perceived identity of odorous stimuli and the ability to recognize the previous occurrence of them. The stimuli comprised 20 relatively familiar odorous objects such as chocolate, leather, popcorn, and soy sauce. Participants rated the familiarity of the odors and sought to identify them. At various intervals up to 7 days after initial inspection, the participants sought to recognize the odors among sets of distractor odors that included such items as soap, cloves, pipe tobacco, and so on. The recognition response entailed a confidence rating as to whether or not an item had appeared in the original set. At the time of testing, the participants also sought to identify the stimuli again. The results upheld previous findings of excellent initial recognition memory for environmentally relevant odors and slow forgetting. The results also uncovered, for the first time, a strong association between recognition memory and identifiability, rated familiarity, and the ability to use an odor label consistently at inspection and subsequent testing. Encodability seems to enhance rather than to permit recognizability. Even items identified incorrectly or inconsistently were recognized at levels above chance.

Adult↗
PubMed1983

Olfactory functioning in temporal lobectomy patients.

Seventeen patients who received unilateral excision of the temporal lobe for intractable epilepsy were compared to 46 normal controls on a battery of tests of olfactory functioning. Tests included quality discrimination, immediate and delayed recognition memory, matching an odor to its visually or haptically presented source, and verbal identification of odors and the function of stimulus objects. In spite of clinically normal absolute sensitivity, the patients performed significantly worse than controls on all tests of olfactory functioning. There were no significant differences in performance between dominant and non-dominant lobectomy patients. Likely explanations for the uniformly impaired performance of patients include deficits in quality discrimination and minor lapses of attention.

Adult↗
PubMed1983

Rectosigmoid perforation and intestinal evisceration from transanal suction.

Transanal suction injuries were sustained in 1981 by five children when they sat upon uncovered swimming area drain sites. Tears of the rectosigmoid areas occurred in each with associated evisceration and loss of substantial amounts of small intestine because of mesenteric separation. These cases are reviewed.

Child, Preschool↗
PubMed1982

Bilateral integration in the common chemical sense.

Human participants judged the pungency of various concentrations of carbon dioxide presented to one nostril, the other nostril, or both (dichorhinic stimulation). Perceived magnitude grew sharply with concentration over the range explored. The combinatorial rule of bilateral integration followed the Pythagorean theorem: the effective mass in a bilateral stimulus equalled the square root of the sum of squares of the mass entering each nostril. This simple rule implies a possible mutual inhibitory interaction between the two nostrils, but it also implies partial spatial summation of the sensory impact of bilaterally presented concentrations. When persons inhale a relatively strong irritant, such as the higher concentrations used here, they will exhibit a very brief reflex interruption of inhalation. An experiment on the threshold for the reflex implied that it too followed the Pythagorean rule of integration. This occurred for both males and females, though females displayed a lower threshold for the reflex, whether evoked unilaterally or bilaterally. This reflex may hold promise as an objective indicator of functional status of the nasal common chemical sense.

Adolescent↗
PubMed1982

Perception of nasal pungency in smokers and nonsmokers.

Two experiments explored the difference in common chemical sensitivity between smokers and nonsmokers. The first experiment confirmed and extended our previous finding that smokers have a higher threshold than nonsmokers for a short-latency, reflex transitory apnea in response to a nasal irritant (carbon dioxide). The experiment revealed that even short periods of smoking (6-10 min) just before the measurement will further impair the smokers's sensitivity to an irritant. Application of the novel scaling technique magnitude matching, whereby persons judged the perceived magnitude of various levels of an irritant, odorant, and tone in the same session, implied that smokers actually perceive irritation less keenly than nonsmokers. The psychophysical functions for pungency in the two groups suggested that the insensitivity may arise from conductive factors (e.g., thickening of the mucus barrier) rather than from neural factors. The results of the scaling and those for the threshold for transitory apnea showed excellent quantitative agreement and indicated that the threshold for the reflex occurred at a criterion level of perceived pungency.

Adult↗
PubMed1982

Reduction of odor and nasal pungency associated with aging.

Aging can seriously blunt suprathreshold sensations mediated by the olfactory receptor system and by common chemical receptors. Despite large individual differences, on the average any given stimulus seemed only about half as intense to the elderly (20 subjects, 65-83 yrs) as to the young (20 subjects, 18-25 yrs). The nature of the loss was a constant percentage reduction of perceived magnitude at stimulus levels from weak to strong. The stimuli were iso-amyl butyrate (a nonirritating fruity odor) and CO2 (which is practically odorless but triggers common chemical sensations effectively). The method used was magnitude matching, by which subjects made numerical estimates of the perceived magnitude of various levels of the two chemical stimuli and of the loudness of low-pitched noises. The loudness estimates served to adjust each subject's chemical estimates to help compensate for individual idiosyncrasies in the use of numbers and potential biases associated with age. Common chemical and olfactory losses seem to be unrelated; aging can dull one sense and leave the other acute.

Adolescent↗
PubMed1981

Odor identification in young and elderly persons: sensory and cognitive limitations.

The investigation sought to uncover whether aging impairs ability to process olfactory information. College-age and elderly women first sought to discriminate among common odors. The elderly persons failed much more frequently than the young. Persons who achieved a high level of discrimination subsequently sought to identify 40 objects by smell and to use personality generated labels to name smells during repeated presentations. The older persons exhibited poorer ability in both tasks. Unlike young persons, the elderly failed to benefit from corrective feedback with their personally generated labels. Nevertheless, the elderly women did benefit from corrective feedback with the true names for the smells. Given enough practice with the true names, the elderly persons could possibly perform as well as the young. Processes that seem to facilitate identification include active encoding, active retrieval, and spontaneous use of verbal mediators. These cognitive operations seem compromised in elderly persons.

Adolescent↗
PubMed1980

Interaction between chemoreceptive modalities of odour and irritation.

Inhaled vapours may stimulate both olfactory receptor cells and endings of the trigeminal nerve. The trigeminal nerve often contributes a pungent, irritating attribute to odours. Many odorants exhibit some pungency when dilute and most become pungent when concentrated. Because the trigeminal system commonly shares the chemosensory burden with olfaction, it is relevant to ask whether these anatomically distinct systems interact. Two obscure psychophysical observations argue for an inhibitory influence of trigeminal over olfactory activity. Katz and Talbert observed that a vapour with both odour and pungency might lose odour at high concentrations, irritation masking odour. The nineteenth century philosopher Alexander Bain, nothing that concentrated carbon dioxide (carbonic acid) evokes pungency, remarked "if a current of carbonic acid accompanies an odour, the effect (odour) is arrested" (ref. 8). We have taken up Bain's forgotten observation and used carbon dioxide to endow otherwise benign concentrations of odorant with varying degrees of pungency. The experiments reported here reveal a strong mutual interaction between pungency and odour, occurring without attenuation even when irritant enters one nostril and odorant the other.

Butyrates↗