Isolated retrograde amnesia.
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Amnesia, Retrograde↗
Biomedical subjects
K Fast
Publications and source records attributed to K Fast.
PROP (6-n-propylthiouracil) supertasters and the saltiness of NaCl.
Taste blindness to phenylthiocarbamide (PTC) and its chemical relative 6-n-propylthiouracil (PROP) was discovered in the 1930s. Family studies showed that those who could not taste PTC/PROP (nontasters) carried two recessive alleles. In recent years, we have classified tasters into two groups: medium (PROP is moderately bitter) and supertasters (PROP is intensely bitter). With our classification, approximately 25% of Americans are nontasters, 50%, medium tasters, and 25%, supertasters. Studies showed that supertasters form a cohesive group. Anatomical studies showed that supertasters have the most fungiform papillae. Psychophysical studies showed that supertasters perceive the most intense bitterness and sweetness from a variety of compounds, the most intense burn from oral irritants, and the most intense tactile sensations from viscous solutions. Oral burn and touch are presumably perceived to be the most intense to supertasters because taste buds in fungiform papillae are innervated by the trigeminal nerve (pain, touch) as well as the chorda tympani nerve (taste). The psychophysical scaling method used was magnitude matching with NaCl as the control modality. With this method, subjects rated the intensities of a series of NaCl and PROP solutions. The assumption that the taste of NaCl did not vary with PROP status allowed comparisons of the bitterness of PROP across subjects. Early magnitude matching studies, using sound as the control, had suggested that this assumption was reasonable. However, recent studies challenged that conclusion. Larger samples with more diverse populations, using sound as the control, showed that the taste of NaCl varied with PROP bitterness; supertasters perceived the strongest taste and nontasters, the weakest. Thus our earlier conclusions were conservative because differences between nontasters, medium tasters, and supertasters were concealed by using NaCl as a standard. Using magnitude matching with sound as the standard, or using the Green scale, which employs intensity labels, we found that the differences between PROP groups are larger. Note that the association between PROP status and salt taste is interesting in itself, since variability in salt taste may have important nutritional consequences.
Humans↗
[Premorbid intelligence diagnosis with the MWT-B(Multiple Choice Word Test-B) in patients with Alzheimer disease].
The usefulness of the multiple-choice word test (MWT-B) was tested as a measure for premorbid intelligence in 107 patients with probable Alzheimer's disease following the NINCDS-ADRDA criteria. The patients were allocated to three groups according to severity of dementia: mild (n = 40), moderate (n = 41) and severe (n = 26). Dementia severity was assessed with the Mini Mental State Test (MMST). The mean of the raw values of the MWT-B (maximum 37) in the group with mild dementia was 28.0 (SD = 5.57), in the group with moderate dementia 23.3 (SD = 8.01), and in the group with severe dementia 6.7 (SD = 8.44), indicating a parallel worsening with the other tests. The MWT-B value of the whole sample correlated with the MMST value (r = 0.70); a significant correlation still existed in patients with mild and moderate dementia. These results confirm that the MWT-B is relevant for dementia. The rate of cerebral glucose metabolism, measured with positron emission tomography (PET) and 18F-fluorodeoxy-glucose (FDG) correlated significantly with the MWT-B scores in the Alzheimer-sensitive temporoparietal region (r = 0.43; P = 0.001) and frontal brain region (r = 0.37; P < 0.05). Whether or not it can be used as a screening measure of dementia will have to be decided on the basis of its scales for sensitivity and specificity.
Aged↗
Exposure to cutting oils and its relation to skin tumors and premalignant skin lesions on the hands and forearms.
In a cohort study the incidence of skin tumors on the hands and forearms of 682 turners exposed to cutting oils was compared to the incidence of the general male population and of office workers. Among the 682 turners, five premalignant squamous cell tumors and eight keratoacanthomas were found between 1960 and 1980. Five of this total of 13 turners with primary skin tumors had another skin tumor as well. Among the 682 men there were four cases of scrotal cancer. Among the 375 office workers examined, no malignant or premalignant tumors or keratoacanthomas were found on the hands or forearms. No primary skin tumors were found among the turners after 1975, when the acid-refined mineral oils were replaced by solvent-refined oils containing a far lower concentration of polyaromatic hydrocarbons, which are probably the cancerogenic agent in the oils. The study shows a greatly increased risk of skin tumors on the hands and forearms of workers exposed to acid-refined mineral oils. Individual susceptibility also seems to be indicated.
Adult↗
Genetic variation and inferences about perceived taste intensity in mice and men.
The study of genetic variation in taste produces parallels between mice and men. In mice, genetic variation across strains has been documented with psychophysical and anatomical measures as well as with recordings from whole nerves. In humans, the variation has been documented with psychophysical and anatomical measures. Whole-nerve recordings from animals and psychophysical ratings of perceived intensities from human subjects have a similar logical limitation: absolute comparisons across individuals require a standard stimulus that can be assumed equally intense to all. Comparisons across whole-nerve recordings are aided by single-fiber recordings. Comparisons across psychophysical ratings of perceived intensity have been aided by recent advances in methodology; these advances now reveal that the magnitude of genetic variation in human subjects is larger than previously suspected. In females, hormones further contribute to variation in taste. There is evidence that the ability to taste (particularly bitter) cycles with hormones in women of child-bearing age, rises to a maximum early in pregnancy and declines after menopause. Taste affects food preferences, which in turn affect dietary behavior and thus disease risks. Valid assessment of taste variation now permits measurement of the impact of taste variation on health. Advances in psychophysical methodology were essential to understanding genetic variation in taste. In turn, the association of perceived taste intensities with tongue anatomy now provides a new tool for psychophysics. The ability of a psychophysical scale to provide across-subject comparisons can be assessed through its ability to show the fungiform papillae density-taste association.
Animals↗