Biomedical subjects

W S Cain

Publications and source records attributed to W S Cain.

At least 19 recordsLinked to original sources

PubMed1995

Relative sensitivity of the ocular trigeminal, nasal trigeminal and olfactory systems to airborne chemicals.

We measured thresholds for eye irritation and odor in homologous series of alcohols (ethanol, 1-butanol, 1-hexanol and 1-octanol), ketones (2-propanone, 2-pentanone, 2-heptanone and 2-nonanone), and alkylbenzenes (toluene, ethyl benzene and propyl benzene). Eye irritation thresholds were well above odor thresholds for all series. Both sensory thresholds declined with carbon chain length, a trend that has implicated lipophilicity in the potency of these and related stimuli. Eye irritation thresholds were remarkably close to nasal pungency thresholds obtained previously in persons lacking olfaction (i.e. anosmics). The agreement between the two thresholds implies that, despite differences in the mucus layer at the two sites and in the epithelial tissue itself, there is remarkable similarity at the site of stimulation. As a practical matter, the eyes could serve as the sites to assess potency for induction of nasal pungency, an assessment previously limited to testing anosmics. Presumably, for our brief stimulus presentations (1-3 s), the differences between ocular and nasal mucosae have little relevance to chemical sensitivity. Studies of the ability of homologous chemical series to evoke threshold eye irritation, nasal pungency and odor not only have practical value, but also can help to define the physicochemical properties of the receptor and perireceptor biophases.

Adult↗

PubMed1992

Sensory irritation. Relation to indoor air pollution.

All mucosae of the body possess chemical sensitivity provided by the CCS. Airborne chemicals can stimulate the CCS through the ocular, nasal, and respiratory mucosae, evoking different pungent sensations, for example, stinging, irritation, burning, piquancy, prickling, freshness, and tingling. Pungent sensations elicited in the nose differ from odor sensations in various characteristics. They are achieved at considerably higher concentrations than those necessary to elicit odor, but they increase with the concentration of the stimulus in a steeper fashion than odor. Pungent sensations from mixtures of compounds show a higher degree of addition--relative to the pungency of the individual components--than that of odor sensations. Pungency is more resistant to adaptation than odor, and, unlike it, displays considerable temporal integration with continuous stimulation. Measurement of a reflex, transitory apnea produced upon inhalation of pungent chemicals holds promise as an objective indicator of the functional status of the CCS. Results from the measurement of this reflex have agreed quantitatively with sensory data in a number of studies, and have shown higher common chemical sensitivity in nonsmokers (compared to smokers), in females (compared to males), and in young adults (compared to the elderly). Research issues mentioned here include the following: 1. We can rarely validate the symptoms putatively caused by indoor air pollution objectively. Without such means, we will always have the potential problem of overreporting and embellishment. Although one person may seem more sensitive than another, the difference may lie in a greater proclivity to complain. 2. Studies of anosmic persons offer a simple means to understand the functional characteristics of the nasal CCS. Studies of chemical series in such subjects should eventually allow construction of quantitative structure-activity models for human pungency perception. The human data can be compared with relevant animal data when possible. 3. The rules of additivity of pungency in mixtures need explication. Regarding the possible role of VOCs in the creation of irritation, we need to ask whether subthreshold levels add up or even amplify each other to produce noticeable irritation. Do repetitive or continuous exposures to subthreshold concentrations increase sensitivity to those substances, so that they evoke pungency when they otherwise would not? Do the various mucose--ocular, nasal, throat--differ in their sensitivity? 4. Modulation of CCS sensitivity by long-term and short-term inhalation of various agents (for example, environmental tobacco smoke) would seem a suitable topic for further research.

Adult↗

PubMed1992

Transcatheter embolization of a high-flow congenital intrahepatic arterial-portal venous malformation in an infant.

An intrahepatic arterial-portal venous malformation (APVM) was diagnosed in a 4 1/2-month-old infant with portal hypertension. Visceral angiography showed a large saccular vascular space in the left hepatic lobe with a multiplicity of feeding arteries and drainage into the left portal vein. The lesion was successfully treated by transcatheter embolization following two unsuccessful surgical procedures. Two years later portal vein thrombosis with cavernous transformation was diagnosed, possibly a consequence of the high-flow arterial-portal shunt and its subsequent occlusion. Knowledge of the anatomic differences between this rare congenital APVM and the more commonly occurring arterial-portal fistula is crucial in planning effective transcatheter embolotherapy or surgery for these lesions.

Arteriovenous Fistula↗

PubMed1992

Congenital diaphragmatic hernia in an era of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization: a prognostic and management classification.

In November 1987 we began to practice delayed repair of acutely symptomatic congenital diaphragmatic hernia (CDH) following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. We reviewed 23 consecutive patients with CDH symptomatic at birth treated over the ensuing 2 1/2 years. The mean age at admission, age at repair, and interval from admission to repair were 4.9, 37.0, and 32.6 hours, respectively. Overall survival was 52% (12/23). ECMO was used in 14 patients with 7 survivors (50%); 4 of these patients underwent repair prior to ECMO and 10 while on ECMO. The patients were retrospectively grouped into three classes based on postductal arterial blood gas (ABG) response to conventional medical management: class A (n = 8), able to achieve and sustain adequate oxygenation (PO2 greater than 60 mm Hg) and hyperventilation (PCO2 less than 40 mm Hg); class B (n = 10), unable to sustain adequate oxygenation (PO2 less than 60 mm Hg) but able to be hyperventilated (PCO2 less than 40 mm Hg); and class C (n = 5), unable to be oxygenated (PO2 less than 60 mm Hg) or hyperventilated (PCO2 greater than 40 mm Hg). The interval from admission to repair was 13.6, 53.5, and 25.4 hours for classes A, B, and C, respectively. Two class A (25%), nine class B (90%), and three class C patients (60%) were placed on ECMO. Survival rates were 88%, 50%, and 0% for classes A, B, and C, respectively. We propose the following management protocol. Class A patients are stable and can be repaired at any convenient point after admission without prerepair ECMO; few will need it afterward.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗

PubMed1992

Olfactory loss and allergic rhinitis.

Olfactory loss is of importance for allergists to investigate in their patients, because if it is due to either allergic rhinitis or nonallergic rhinitis, it is potentially reversible. One should be sure to consider nasal polyposis and inflammation from chronic sinusitis, especially of the ethmoidal sinuses. Simple screening in the office can be achieved with an odor identification test of widely available substances as described above. Should there be no response to treatment or if the patient has a history of chronic sinusitis, recalcitrant nasal polyposis, or previous otolaryngologic procedures, further evaluation including rhinoscopy may be required. Recent olfactory loss in the absence of nasal symptoms and in the absence of abnormalities in the nasal cavity should suggest further investigation to look for a more central process. Morphologic investigation with electron microscopy of the olfactory epithelium and the superior nasal cavity is just beginning. The impact of inflammation in this area awaits investigation.

Adult↗

PubMed1991

Improvement in survival of patients with congenital diaphragmatic hernia utilizing a strategy of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization.

Patients with congenital diaphragmatic hernia (CDH) symptomatic at birth treated at this institution over the past 6 years were reviewed. The patients were divided into two chronological groups for analysis: group 1, consisting of 15 patients treated from January 1984 through October 1987, a period during which acute CDH was considered to be a surgical emergency; and group 2, comprising 20 patients treated from November 1987 through October 1989 using a management protocol of delayed repair following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. These two groups did not differ significantly in gestational age, birth weight, Apgar scores, hernia side, or age at admission. Group 2 had a longer mean interval from admission to repair (26.5 v 1.8 h, P = .01) and average age at repair (31.0 v 6.5 h, P = .02) than did group 1. Prosthetic closure of the diaphragmatic defect was required more frequently in group 2 then in group 1 (63% v 31%, P = .07). Survival in group 2 was significantly greater than in group 1 (55% v 20%, P = .04). Seven group 2 patients (35%) achieved a prerepair or pre-ECMO PO2 greater than 100 mm Hg and all survived; four of the 13 "nonresponders" also survived. ECMO was used in 11 group 2 patients with five survivors (45%); four of these patients underwent repair prior to ECMO and seven underwent repair while on ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal Membrane Oxygenation↗

PubMed1991

Nasal pungency, odor, and eye irritation thresholds for homologous acetates.

We measured detection thresholds for nasal pungency (in anosmics), odor (in normosmics) and eye irritation employing a homologous series of acetates: methyl through octyl acetate, decyl and dodecyl acetate. All anosmics reliably detected the series up to heptyl acetate. Only the anosmics without smell since birth (congenital) reliably detected octyl acetate, and only one congenital anosmic detected decyl and dodecyl acetate. Anosmics who lost smell from head trauma proved to be selectively less sensitive. As expected, odor thresholds lay well below pungency thresholds. Eye irritation thresholds for selected acetates came close to nasal pungency thresholds. All three types of thresholds decreased logarithmically with carbon chain length, as previously seen with homologous alcohols and as seen in narcotic and toxic phenomena. Results imply that nasal pungency for these stimuli rests upon a physical, rather than chemical, interaction with susceptible mucosal structures. When expressed as thermodynamic activity, nasal pungency thresholds remain remarkably constant within and across the homologous series of acetates and alcohols.

Acetates↗

PubMed1991

On the discrimination of missing ingredients: aging and salt flavor.

This study reports on the ability of young, middle-aged, and elderly persons to discriminate the presence-absence of the salt flavoring in a published recipe for a soup. Although all but one young person tested was able to make this discrimination above chance level, more than half of each of the two older groups failed to do so. Both the discrimination score and the absolute threshold for NaCl in water solution correlated significantly with age over a span from 18 to 89 yrs. These results add to previous ones from a similar study of the discrimination of an aromatic spice, marjoram (Cain et al., 1990), in demonstrating that taste and smell weakness revealed in recent psychophysical tests can reveal themselves in the perception of everyday food and beverage preparations. A secondary study compared thresholds for NaCl in water with NaCl thresholds in the presence of tomato, the principal ingredient of the published recipe. These thresholds, presumably because of "mixture suppression" of tastes, were from seven to ten times higher than thresholds in water. Although thresholds for young and old were more alike in the tomato medium than in water, the elderly nevertheless needed over twice as much salt concentration than did the young just barely to appreciate its presence. Computer evaluation of the salt content of a large number of soup recipes revealed that (a) the salt content of the tomato soup we used to study discrimination was reasonably representative of other published recipes for tomato soups and (b) that the salt content of the average of these tomato soup recipes was greater than that of the average of non-tomato soup recipes.

Adult↗

PubMed1991

Olfactory sensitivity: reliability, generality, and association with aging.

Thirty-two Ss between 22 and 59 years of age yielded detection thresholds for 4 odorants over 4 sessions. The thresholds decreased and reliability increased over the course of testing. High intercorrelations between odorants and the stability of an S's relative position within the threshold distributions showed that a general factor of sensitivity dominated the outcome. Age contributed strongly to intersubject variation. Even among these nonelderly individuals, it accounted for up to 2 orders of magnitude in threshold performance. Other important factors included superiority of the right nostril and a negative correlation between the mean and variance of threshold distributions. Scant attention to the correlation may have contributed to overestimation of the frequency and specificity of specific anosmia. A clinically relevant outcome was that measurement of threshold for diagnostic purposes can generally rely on just 1 odorant.

Adult↗

PubMed1991

Remembered odors and mental mixtures: tapping reservoirs of olfactory knowledge.

Five experiments explored how (a) perceived and remembered odor intensities relate to concentration; (b) odor intensities integrate in perceptual, memorial, and mentally constructed mixtures; and (c) components vary in intensity in physical versus mental mixtures. Ss estimated the magnitude of unmixed stimuli presented physically (perceptual estimation) or represented symbolically (memorial estimation). Ss also judged mixtures and their components in combinations of perceptual and memorial presentation. Power functions with similar exponents described the relations between both perceived and remembered intensity and concentration. Perceptual, memorial, and mental mixtures all followed much the same interactive rule of integration. Correspondingly, the intensities of components varied similarly in mentally constructed and physical mixtures. The results imply intensive invariance across odor perception and odor memory.

Adult↗

PubMed1991

Sensory and semantic factors in recognition memory for odors and graphic stimuli: elderly versus young persons.

In four experiments, young (18-26 years, M = 21) and elderly (over 65 years, M = 72) people were compared for recognition memory of (a) graphic stimuli (faces of presidents and vice presidents, engineering symbols, and free forms) and (b) everyday odors. On graphic stimuli, the elderly consistently matched the young, but on odors the performance of the elderly was worse. Their poorer olfactory performance was observed after only 26 s, but became truly marked after 1 hr or more. Somewhere between 1 hr and 2 weeks, their odor performance fell to chance, but their graphic performance remained well above chance. Although the young did forget both graphic and odor materials progressively, their performance always stayed above chance over a 6-month period. Experiments 1 and 2 revealed that the elderly are less sensitive to odors than the young (with thresholds about 10-fold higher), which may explain, in part, their poorer olfactory memory performance. Knowledge that the subjects brought to the tasks by way of familiarity with and ability to name odors and faces played a positive role in recognition memory. Because of this positive role, together with the negative role played by verbal distraction, we conclude that odor recognition memory depends, perhaps heavily, on semantic processing. Impaired semantic processing may result even when odors are simply rendered desaturated, or pastel because of the weakening of olfactory sensitivity with aging.

Adolescent↗

PubMed1990

Thresholds for odor and nasal pungency.

Detection thresholds were measured repeatedly for 11 chemicals in normosmic and anosmic subjects. The stimuli comprised the first eight members of the series of n-aliphatic alcohols, phenyl ethyl alcohol, pyridine, and menthol. Results showed that anosmics could detect, via pungency, all but phenyl ethyl alcohol reliably. In the aliphatic series, both odor and pungency thresholds declined with chain length in a way that implied dependence of both in part on phase distribution in the mucosa. Odor thresholds, however, declined more rapidly than pungency thresholds: the ratio of anosmics threshold/normosmics threshold increased from 23 for methanol to 10,000 for 1-octanol. The outcome of a scaling experiment employing normosmic subjects indicated that, with the exception of methanol and ethanol, pungency arose when perceived intensity reached a narrowly tuned criterion level. When thresholds were expressed as percentages of saturated vapor, an index of thermodynamic activity, thereby accounting for differences in solubility and in phase distribution in the mucosa among the various stimuli, both odor and pungency thresholds depicted a striking constancy across stimuli.

Adult↗

PubMed1990

Odor intensity of mixed and unmixed stimuli under environmentally realistic conditions.

Subjects judged the odor intensity of single odorants and binary mixtures of fixed or varying proportions presented in the atmosphere of an environmental chamber. The subjects were exposed to the vapors either continuously (15 min) or periodically (once a minute for 15 min). As found previously, the mixtures smelled less intense than predicted from the simple sum of their unmixed components. The degree of hypoadditivity proved about the same for the four pairs of odorants studied, but varied from periodic to continuous exposure. Periodic exposure led to a greater departure from simple additivity and confirmed the presence of the phenomenon of compromise whereby the mixture can smell less intense than its stronger component alone. Continuous exposure led to a closer approximation to simple additivity and exhibited no compromise. Nevertheless, the behavior seen under continuous exposure apparently derived from a tendency for mixtures to exhibit less adaptation than their components. Whereas mixtures may seem to lack potency relative to their unmixed components, they may in fact compensate for any deficiency in momentary intensity through an increase in durability.

Attention↗

PubMed1990

Missing ingredients: aging and the discrimination of flavor.

An experiment explored how well young, middle-aged, and elderly subjects could discriminate the presence or absence of the spice marjoram in a soup prepared according to a published recipe. Whereas most young made the discrimination at a level above chance, most middle-aged and elderly failed to. A clinical test that entails odor threshold and identification revealed that olfactory ability also diminished with age among these subjects. Furthermore, the odor thresholds measured in the test correlated significantly with the subjects' ability to discriminate flavor. Subsequent testing wherein subjects sought to discriminate flavor with their noses blocked confirmed that olfactory ability largely underlay the discrimination. The results emphasize that losses in olfaction measured most commonly with environmental odors are serious enough to have an impact on discrimination of flavors in everyday foods, even among persons of middle age. Loss of such discriminative capacity may entail risks of avoiding dangerous and overlooking beneficial ingredients in foods.

Adult↗

PubMed1989

Olfactory adaptation and recovery in old age.

Four experiments are reported in which it is shown that elderly adults are more prone than young adults to olfactory adaptation and are slower to recover threshold sensitivity. The first three experiments differed in detail, but had in common an initial threshold determination for 1-butanol, a 30 s exposure to a concentration twenty-seven times threshold, followed by repeated presentation of the initial threshold level at various intervals after adaptation. In three experiments accuracy of forced-choice discrimination was poor immediately after adaptation but tended to improve with time, and considerably faster in the young than in the elderly. In the fourth experiment, groups of twenty-three elderly and twenty-five young subjects threshold-matched for pyridine were compared. The subjects participated in three sessions in which pyridine was infused into a test chamber at either 2.5, 1.25, or 0 L min-1 (sham session). At 2.5 L min-1 both groups were able to track the buildup of odor intensity during infusion and its decline after infusion. In contrast, at 1.25 L min-1 only the young were able to track odor intensity, even though the concentration rose above initial threshold levels.

1-Butanol↗

PubMed1989

Uniformity of olfactory loss in aging.

Most studies of how human olfaction changes with age have compared young and old. Essentially all such studies imply that aging takes a toll. The elderly have higher thresholds, perceive suprathreshold odors as being weaker, discriminate quality less well, recognize and identify common odors less well, and remember episodic presentations of odors poorly. To a first approximation, it appears that all odor qualities and functions undergo a general blunting. The few studies of persons between the young and the elderly suggest that the process of deterioration sets in early and progresses gradually. Such gradual deterioration would presumably allow the easiest accommodation to any loss and may account for why many elderly people seem oblivious to it. In some respects, ignorance may be bliss. For example, the diminished flavor of food may go unnoticed. In other respects, the loss of olfactory information may pose some nutritional and safety risks of which the elderly and perhaps even the middle-aged should be apprised. Longitudinal studies would seem to offer the only chance to decide the rate and magnitude of individual losses in olfaction. Such studies might also offer enlightenment regarding ways to forestall loss.

Adult↗

PubMed1989

Testing olfaction in a clinical setting.

Assessment of olfactory functioning at the CCCRC entails a threshold test and an odor identification test that contains eight everyday items. A performance average on the two tests yields a composite score on a scale from 0 (anosmia) to 7 (normosmia). The performance of normal volunteers is stable over most of an individual's life span, but decreases for persons over the age of 65 years. Approximately half the patients with olfactory complaints display anosmia, and the other half have hyposmia. The distribution of scores, however, varies with etiologic category, emplified by the fact that patients with nasal/sinus disease display anosmia more frequently than hyposmia. The tests can determine cause (e.g., improvement of score with corticosteroid treatment in cases of nasal/sinus disease) and can also assess degree of improvement with treatment, such as sinus operation.

Aged↗

PubMed1988

Evaluation of olfactory dysfunction in the Connecticut Chemosensory Clinical Research Center.

The olfactory test administered to patients at the Connecticut Chemosensory Clinical Research Center combines stability of outcome with sensitivity to variables known to affect olfaction (age, sex). The test, which pairs an odor threshold component with an odor identification component, readily resolves differences in function between patients and controls. It reveals differences in the distribution of functioning for various probable causes (nasal/sinus disease, postupper respiratory infection, and head trauma), proves sensitive to improvements in function caused by therapeutic intervention (ethmoidectomy, steroid administration for nasal/sinus disease), and correlates with objective signs of nasal/sinus disease (visual exam, x-ray). The two components of the test agree well, though the odor identification component seems somewhat more sensitive than the threshold component as currently designed.

Adolescent↗