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Biomedical subjects

R A Fox

Publications and source records attributed to R A Fox.

At least 127 records · Page 7Linked to original sources
PubMed1984

Effect of lexical status on phonetic categorization.

To investigate the interaction in speech perception between lexical knowledge (in particular, whether a stimulus token makes a word or nonword) and phonetic categorization, sets of [bVC]-[dVC] place-of-articulation continua were constructed so that the endpoint tokens represented word-word, word-nonword, nonword-word, and nonword-nonword combinations. Experiment 1 demonstrated that ambiguous tokens were perceived in favor of the word token and supported the contention that lexical knowledge can affect the process of phonetic categorization. Experiment 2 utilized a reaction time procedure with the same stimuli and demonstrated that the effect of lexical status on phonetic categorization increased with response latency, suggesting that the lexical effect represents a perceptual process that is separate from and follows phonetic categorization. Experiment 3 utilized a different set of [b-d] continua to separate the effects of final consonant contrast and lexical status that were confounded in Experiments 1 and 2. Results demonstrated that both lexical status and contextual contrast separately affected the identification of the initial stop. Data from these three experiments support a perceptual model wherein phonetic categorization can operate separately from higher levels of analysis.

Humans↗
PubMed1984

The electron density of bone for inhomogeneity correction in radiotherapy planning using CT numbers.

A CT scanner has been used to measure the electron density of a range of bone types in vivo. It is shown that there is a linear relationship between the CT number of bone and its electron density, which is expected theoretically if different bone types are treated as a variable mixture of osseous material and marrow. A method of calibrating any CT scanner using a simply prepared solution is proposed, which should enable electron densities of bone to be estimated from CT numbers with an accuracy of 5%.

Adult↗
PubMed1984

Off-vertical rotation produces conditioned taste aversion and suppressed drinking in mice.

The effects of off-vertical rotation upon the intake of tap water immediately after rotation, and upon conditioned taste aversion, were assessed in mice with the tilt of the rotation axis varying from 5 to 20 degrees from the earth-vertical. Conditioned taste aversion occurred in all mice that were rotated, but the intake of tap water was suppressed only in mice that were rotated at 15 or 20 degrees of tilt. The greater suppression of tap water intake and the stronger conditioned aversion in the mouse as the angle of tilt was increased in this experiment are consistent with predictions from similar experiments with human subjects where motion sickness develops more rapidly as the angle of tilt is increased. It was suggested that off-vertical rotation may be a useful procedure for insuring experimental control over vestibular stimulation in animal studies of motion sickness.

Animals↗
PubMed1984

Immunological abnormalities in patients with chronic bronchial suppuration: a possible relationship with endotoxaemia.

Chronic bronchial suppuration has been associated with elevations in immunoglobulin levels, circulating autoantibodies and immune complexes but the cause is obscure. In order to investigate one possible explanation we studied eight male subjects (mean age 54.9 years, range 39-68) and 16 female subjects (mean age 45.2 years, range 24-68) with bronchial suppuration attributed to bronchiectasis. Gram-negative organisms were found in the sputum of 95% of subjects. Forty per cent (10 subjects) had elevations in immunoglobulin levels and 60% (15 subjects) had circulating autoantibodies. Eighty-eight per cent (21 subjects) had mild-moderate increases in the level of C-reactive protein. Endotoxin was detected using the limulus amoebocyte lysate test in 50% (12 subjects). Endotoxin was found only in patients with an immunological abnormality and was more likely to be detected in those with both elevated immunoglobulins and circulatory autoantibodies. It is suggested that the endotoxin may be of aetiological significance in the development of autoantibodies and elevations of immunoglobulin levels.

Adult↗
PubMed1983

Endogenous inhibitors of monoamine oxidase present in human cerebrospinal fluid.

Inhibitory activity against the enzyme monoamine oxidase is present in low molecular weight fractions (less than 100,000) of human cerebrospinal fluid. These endogenous substances of different molecular weights (3000 to more than 35,000) act like monoamine oxidase inhibitor drugs to inhibit both type A and type B monoamine oxidase.

Animals↗
PubMed1983

Necropsies in the elderly.

A retrospective analysis of 332 necropsies in the over-65-year-olds and 129 necropsies in the over 85-year-olds (overall necropsy rate 35%) showed that the commonest cause of death in elderly patients admitted acutely to hospital was pneumonic illnesses. 27-31% of the necropsies revealed the presence of a potentially treatable contributory factor to death that was undiagnosed during life. In only 4.5% of the necropsies in the over-85-year-olds was the cause of death uncertain.

Acute Disease↗
PubMed1983

Response to ionising radiation in Duchenne muscular dystrophy.

Using lymphoblastoid cell cultures the response to gamma (gamma)-radiation, was examined in 6 Duchenne muscular dystrophy (DMD) patients; 2 clinically normal males as negative controls, and 2 patients with ataxia telangiectasia (AT) showing sensitivity to ionising radiation as positive controls. In a series of experiments, cell recovery and growth at day 2 post radiation, was determined after 5 separate gamma-irradiation dose levels: 50, 100, 150, 200 and 300 rads. The DMD cell strains showed a radiation dose response that was significantly greater than in cells from 2 normal males, while both DMD and normal cells were significantly less responsive than were AT-sensitive cell strains.

Adolescent↗
PubMed1983

The frequency of physical signs usually attributed to meningeal irritation in elderly patients.

Nuchal rigidity, which may be a sign of meningitis, was found in 35 per cent of geriatric patients on acute-care and rehabilitation wards and in 13 per cent of younger patients on an acute-care ward. It was significantly associated with cerebrovascular disease, confusion, abnormal plantar responses, and primitive reflexes. Elderly patients who have nuchal rigidity with no history of neurologic or cognitive disorders should be investigated for meningitis.

Adolescent↗
PubMed1983

Gynecologic sepsis as a cause of covert infection in old age.

Three cases of endometritis, which presented covertly in elderly women, are described. All three patients were in a poor state of nutrition, and two had serious intercurrent disease. It is believed that cyclical shedding of the endometrium and "normal" vaginal flora (under the influence of estrogen) are the major defenses against infection. These are lost after the menopause, and were therefore absent in the three patients described here. The waning of the immune response associated with aging, particularly the progesterone-stimulated uptake of polymeric IgA in the endometrium, may be important, as may the immunosuppressive effect of malnutrition. It is suggested that a nonspecific deterioration in an elderly woman or infection of uncertain site should prompt a careful re-examination, including a thorough pelvic examination.

Aged↗
PubMed1982

Macrophage migration inhibition factor (MIF): reducing the variables.

While the phenomenon of macrophage migration inhibition is a useful indicator of lymphokine release, it may be caused by other substances, it is subject to considerable variability, and it may be masked by the concomitant presence of substances stimulating migration. We have investigated certain aspects of the lymphokine macrophage interaction in order to circumvent these problems. Cells from the murine macrophage cell line RAW 264-7 migrated with less variability than fresh guinea pig peritoneal macrophages and were more sensitive target cells for human macrophage migration inhibition factor (MIF). Assays were performed with serum-free and endotoxin-free medium and in all cases in the presence and absence of L-fucose. This added specificity to the assay in that biological MIF activity was invariably blocked by L-fucose whereas migration inhibition produced by antigen complexed antibody, endotoxin, and periodate was not affected by L-fucose. It was also possible to demonstrate MIF activity in mixtures of MIF and migration stimulation factor by using L-fucose. We suggest that MIF activity is determined with less variability by using a macrophage cell line as indicator cells and performing the assays in the presence and absence of L-fucose.

Animals↗
PubMed1982

Lymphokine responses to mitogenic and antigenic stimulation. Predictive value in renal transplantation.

Immune responsiveness of recipients of renal transplants from cadaver donors was monitored by measuring lymphokine responses to specific (donor antigen) and nonspecific (concanavalin A (Con A)) stimuli. Production of migration inhibition factor (MIF) in response to stimulation by Con A before and 3 days after transplantation correlated strongly with graft rejection and production of migration stimulation factor (MSTF) with graft acceptance. This pattern continued at later time intervals but was more variable. An initial vigorous MIF response to donor cell extract was associated with rejection but subsequent responses to donor extract in the 1st month after transplantation were variable and not predictive of the outcome. In some cases, there was clearly a dissociation of lymphokine responses to donor-specific and nonspecific stimuli.

Animals↗
PubMed1982

The white nails of old age (neapolitan nails).

Nail changes similar to those reported by Terry and Lindsay were defined in an elderly inpatient population. Two hundred fifty-eight patients were studied, and an overall incidence of 19 per cent was found. There was no significant difference between men and women. The only significant correlations in this study were with osteoporosis and thin skin. Eight men with nail changes were compared with seven men without such changes by calculating the metacarpal index of cortical bone mass. The index was much lower in patients with nail changes (t = 2.64; P less than 0.01). All patients with nail changes had thin skin. No correlations were found with serum albumin, liver function, or kidney function. These nail changes are less frequent in the "less frail" elderly living in the community. Changes of the Terry type are common in children but disappear by early adult life. It is suggested that the nail changes are age-related phenomena and that they may reflect an underlying disturbance of collagen being manifested as changes in the nail bed, skin, and bone.

Aged↗
PubMed1982

Individual variation in the perception of vowels: implications for a perception-production link.

A scaling experiment using dyadic comparisons of vowel pairs was performed to determine if significant perceptual variation existed on an individual level and whether such variation could be correlated with differences among subjects in their production of vowels. Subjects were required to scale six separate sets of vowel stimuli. Each stimulus set consisted of the 36 possible dyads from the vowel set /(see formula text)/. Analysis of the resulting data indicated that significant individual perceptual variation was present which could be seen as a function of perceptual structure differences between the subjects and not merely error variance. In addition, such variations were related to aspects of each subject's acoustic vowel space - indicators of tongue height and advancement during vowel articulation. These results were interpreted as suggesting a link between perception and production.

Analysis of Variance↗
PubMed1982

A study of t cell populations in alcoholic cirrhosis and chronic alcoholism.

It has been suggested that the various immunological abnormalities found in patients with cirrhosis might have contributed to the development of liver disease. T cells and their subpopulations were enumerated in patients with alcoholic cirrhosis, in patients with severe alcoholism but no detectable liver disease, and in 2 control groups (non-drinkers and social drinkers) in an attempt to determine which changes, if any, are related to and a result of cirrhosis, and which are related to alcoholism and therefore contributing factors in the pathogenesis of cirrhosis. Patients with alcoholic cirrhosis were found to have a decreased percentage of T cells, but the normal %s of B cells and monocytes when compared with controls. There were no differences between the 4 groups in the %s of T cells composed by the subset that rosette with ox red cells coated with IgM anti-ox erythrocyte antibody (T mu cells). However, the %s of T cells composed by the subset that rosette with ox red cells coated with IgG anti-ox erythrocyte antibody (T gamma cells) were found to be significantly decreased in patients with chronic alcoholism when compared with controls, and in patients with alcoholic liver disease when compared with chronic alcoholics. Many factors contribute to the development of cirrhosis: low numbers of T gamma cells may be an indication of individual susceptibility to progressive liver disease in patients with chronic alcoholism.

Adolescent↗
PubMed1982

Arthritis in the elderly.

In old age, particularly in those over the age of 75 years, the disease process is operating in a unique setting. The awareness of this uniqueness has been slow in coming to the attention of the medical profession but the weight of clinical experience imposed by demographic change in the population has made this an urgent consideration. Arthritis presents in a setting where there are multiple ageing or degenerative features and it occurs frequently in conjunction with other diseases. Early and accurate diagnosis is of paramount importance in the elderly because of the many interacting factors and the fragile 'milieu interieur'. Judicious use of drugs with close monitoring is essential if the patients's well being is to be improved and the morbidity reduced. Joint disease, osteoarthritis and rheumatoid arthritis make a significant contribution to disability and dependence in the elderly and have certain features which are more common than those found in the younger age groups.

Aged↗
PubMed1982

Conditioned feeding suppression in rats produced by cross-coupled and simple motions.

Conditioned feeding suppression was produced in rats by earth-vertical rotation, seesaw acceleration, and cross-coupled accelerations. Rats were exposed to 15 min of motion immediately after eating a sweet, novel food. The effects of this motion were assessed by measuring consumption of sweet food during a second feeding session that was 72 hr after exposure to motion Exposure to cross-coupled accelerations produced the greatest conditioned suppression of feeding. Progressively less suppression resulted from exposure to seesaw acceleration and to rotation. This ordering of suppression effects is consistent with the amount of vestibular stimulation produced by these motions. These results indicate that conditioned feeding suppression in rats can be produced by vestibular stimulation of a duration known to produce frank motion sickness in other animals and man.

Acceleration↗