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Biomedical subjects

D Rose

Publications and source records attributed to D Rose.

At least 199 records · Page 11Linked to original sources
PubMed1980

The binocular: monocular sensitivity ratio for movement detection varies with temporal frequency.

Binocular sensitivity to the movement or flicker visible in a phase-reversing grating pattern is higher by a factor of about 1.7 to 2.0 compared with monocular sensitivity, at low rates of phase reversal. This factor decreases as the temporal frequency of the phase reversal increases, especially above 10 Hz. For different observers, the ratio may be higher or lower overall with gratings of spatial frequency 5 cycles deg-1 than with 0.5 cycle deg-1 gratings.

Eye Movements↗
PubMed1980

The Palo Alto Destructive Content Scale as a predictor of physical assaultiveness in men.

The Palo Alto Destructive Content Scale was developed to assess assaultive behavior in men in Veterans Hospital settings. It involves scoring each response on the Rorschach test for the level of destructive aggression. Five groups of men who were, or currently are, at Atascadero State Hospital were studied. The groups consisted of assaultive non-reoffenders, assaultive roeffenders, rapists, murderers, and nonassaultive child molesters. Each group was administered the Rorschach test while they were at the hospital and the mean Palo Alto Destructive Content Score was computed. The results indicate significant differences between non-reoffenders and reoffenders. There were no significant differences between the following groups: non-reoffenders vs. non-assaultive patients; reoffenders vs. assaultive patients and murders vs. rapists. The core issue in the treatment of assaultive offenders appears to be hostility and its capability for overt expression.

Adult↗
PubMed1979

A low frequency mosaicism for monosomy 21 in a live born female.

Monosomy 21, whether homogeneous or as a mosaicism, is very uncommon. We report here a 3-month-old white female with a low degree of monosomy 21 in the blood karyotype (6.5%, 110 cells counted) but not in the skin fibroblasts, which contained only the normal chromosome complement. The patient's physical features included microcephaly with frontal slanting; prominent occiput; ridge-shaped sutures; agenesis of the corpus callosum; large, prominent ears; high and narrow palate; micrognathia; tetralogy of Fallot; crowded toes; and dry, thick skin with very little subcutaneous tissue. The case is discussed in light of the suggested clinical features of the "monosomy 21" syndrome and the possible implications of such a low-grade mosaicism in prenatal diagnosis.

Abnormalities, Multiple↗
PubMed1979

An analysis of the variability of unit activity in the cat's visual cortex.

The spontaneous firing of single units in the cat's visual cortex, and their responses to repeated presentations of a constant visual stimulus, have been analysed quantitatively. Although the responses of most cells showed some habituation to the stimulus, this was less extensive than the fluctuations in responsiveness which occurred from one set of presentations to the next, over the course of several minutes. Fluctuations occurred largely independently in both the spontaneous and the stimulus-evoked firing of the cell. This suggests that separate mechanisms determine spontaneous and evoked firing. Quantitative estimates of the reliability (the reciprocal of the variability) of responses were higher if the peak firing rate of the cell was measured, rather than the total number of spikes fired by the cell. Thus, peak firing rate is more likely than total spike count to be the signal of biological significance.

Animals↗
PubMed1979

Changes in somatomedin-like activity and concentrations of growth hormone and prolactin in the plasma of castrated growing lambs.

Somatomedin-like activity was measured in the plasma of growing lambs using the porcine costal cartilage disk assay. Plasma concentrations were found to be high initially at 2 days of age (mean potency 1.02 plus or minus 0.13 (SEM) units/ml, n = 4) declined significantly by 8 days of age (mean potency 0.65 plus or minus 0.04 units/ml, n = 5, P less than 0.01, analysis of variance). Thereafter somatomedin-like activity declined slowly to reach its lowest concentration at 146 days of age (mean potency 0.61 plus or minus 0.04 units/ml, n = 5) then it rose slowly until 288 days of age (mean potency 0.61 +/- 0.04 units/ml, n = 5. These changes in somatomedin-like activity were accompanied by high initial plasma concentrations of growth hormone (24.8 plus or minus 4.8 ng/ml, n = 5) which declined under 188 days of age (2.8 plus or minus 0.04 ng/ml, n- 5) and then rose slightly until 288 days of age (13.8 plus or minus 9 ng/ml, n=5). Plasma prolactin concentrations showed a different pattern being low initially (47.8 plus or minus 8.7 ng/ml, n = 5) rising until 146 days of age (203 plus or minus 16 ng/ml, n = 5) and then declining to low value for the rest of the experiment. The relationships between these factors is not clear but somatomedin-like activity shows a pattern in the lamb which is highest when growth is faster (i.e. in the young lamb).

Animals↗
PubMed1979

Facilitation of bicuculline- and picrotoxin-induced seizures by sodium valproate in rats.

Paralysed rats anaesthetized with urethane or halothane were injected with bicuculline or picrotoxin at doses which induced seizure activity in the EEG. Sodium valproate (50--1200 mg/kg) or saline was injected i.p. and its effect on the amplitude and duration of the seizures was measured. The seizures induced by either convulsant were increased significantly by doses of valproate greater than or equal to 200 mg/kg. The sites of action of the drugs in the brain, and the possible transmitter mechanisms involved, are discussed.

Animals↗
PubMed1978

Monocular versus binocular contrast thresholds for movement and pattern.

The superiority of binocular vision over monocular vision has been compared for the detection of stationary sinusoidal grating patterns, and for the detection of the apparent movement induced by rapidly phase-reversing such gratings. The thresholds for binocular and monocular pattern perception were in the ratio 1:2 1/2, as found by previous workers. For apparent movement, however, binocular thresholds were lower than monocular thresholds by a factor of 1.9; for every subject tested (n = 20) the ratio for movement detection was larger than the ratio for pattern detection. The effects of combining inputs from the two eyes cannot be explained solely by linear summation models, but may in some circumstances depend on the nonlinearities of certain types of nerve cell.

Form Perception↗
PubMed1977

Effects of LSD on the response of single units in cat visual cortex.

The effects of intravenous doses (200 mug) of LSD on the activity of single neurones in the primary visual cortex have been studied in cats anaesthetized with urethane. Cells were stimulated with a bright bar of light moved over the receptive field, and orientation tuning was assessed quantitatively before and after administration of the drug. Changes in neuronal activity were compared with those observed in a control sample of cells recorded when the cats were given no drug. LSD increased the responsiveness of some cells to visual stimuli and decreased that of others, but some cells were not affected. The changes in responsiveness were dose dependent; the larger doses of the drug (expressed in mug/kg body weight) tended to depress the responses and the smaller doses to enhance them. The effects appeared earlier in complex cells than in simple cells. Changes in spontaneous activity, direction selectivity and orientational properties were found in some cells.

Animals↗
PubMed1977

Responses of single units in cat visual cortex to moving bars of light as a function of bar length.

1. The responses of single units in the cat's primary visual cortex to moving bars have been examined quantitatively as a function of bar length.2. For about half the cells studied, very long bars evoked weaker responses than short bars, implying that there were inhibitory regions flanking the receptive field centre. In another quarter of the cell sample, there was evidence of flanking regions which were facilitatory in effect.3. The strength of the flanking regions was found to vary from cell to cell and there was no sudden transition between cells which were ;hyper-complex' and those which were not.4. Within the central region of the receptive field, the responses of most (but not all) cells increased with bar length. About half the cells responded to very short bars or spots of light, but about one in six would not respond at all to short bars.5. Correlations were sought between the properties of cells as simple or complex, their responsiveness to moving spots of light, the size of their receptive field centre and the polarity, strength and size of their receptive field flanks. Simple and complex cells with small receptive fields were more likely to respond well to spots, and to have strong inhibitory flanks.6. Correlations were also sought between the above properties and several other parameters of cell behaviour. Cells with strong inhibitory flanks were found to be more broadly tuned for orientation. Individual cells were also more broadly tuned for the orientation of short bars than of long bars.7. Evidence was obtained that spatial summation can be linear or non-linear for different cells.

Action Potentials↗
PubMed1976

Clinical correlation of strain differentiation of Neisseria gonorrhoeae.

An in vitro bactericidal assay that utilized a set of 20 typing antisera to Neisseria meningitidis was developed to distinguish differences in strains of Neisseria gonorrhoeae based on patterns of killing. When test conditions were rigidly standardized, the method was sensitive and reproducible. Strains of gonococci from 20 unrelated patients had 20 different patterns of killing. Sets of strains of N. gonorrhoeae that were likely to be identical on the basis of clinical histories were examined. Organisms isolated from consorts reacted in an identical fashion in seven of nine instances. The two nonidentical sets of strains from consorts were also different in their antibiotic sensitivity patterns. The case history of one patient suggested that one of these strains was obtained from a source of infection other than the named consort, and a second patient was reinfected with a strain from her partner four months later. Four sets of strains were cultured at different intervals after appropriate therapy. On the basis of bactericidal patterns, the strains from one patient were the same, a finding that suggested treatment failure; the strains from other patients were not identical, a fact that suggested that patients were reinfected.

Antigens, Bacterial↗