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Biomedical subjects

M J Wright

Publications and source records attributed to M J Wright.

At least 109 records · Page 6Linked to original sources
PubMed1980

Ultrasonic effects on alveolar macrophages in suspension.

Rabbit alveolar macrophages in suspension were exposed to 5 or 10 min of continuous 2-MHz ultrasound with 5, 10, and 15 W/cm2 spatial average intensities. Viability as determined by dye exclusion decreased with increasing intensity. Pressure experiments indicated that this was a result of acoustic cavitation. Ultrasound induced clumping of cells and often reduced membrane ruffling. Some cells were disintegrated. Cells that appeared to be otherwise intact had swollen mitochondria with ruptured cristae.

Animals↗
PubMed1979

The mechanism of peripherally evoked responses in retinal ganglion cells.

1. Responses to stimulation of retinal regions remote from the classical receptive field were recorded from optic tract fibres in lightly anaesthetized cats. 2. X- and Y-cells gave reliably different responses to the sudden reversal of the phase of a high contrast grating that fell on the retina more than 15 deg from the centre of the receptive field. 3. The mechanism that generates these responses ('shift effect' or 'periphery effect') in Y-cells is insensitive to the spatial phase of the stimulating grating. It can resolve gratings of higher spatial frequency than can be resolved by the classical receptive field mechanisms of Y-cells but its temporal resolution is poorer. 4. Signals that contribute to peripherally evoked responses are accumulated over a region that extends to at least 35 deg from the centre of the receptive field. Although this region is not uniformly sensitive, regions in the periphery of the visual field are as effective as regions around the area centralis in eliciting the responses, and do not require coarser gratings. 5. In some Y-cells the response to peripheral stimulation was amplified by increasing (on-centre units) or decreasing (off-centre units) the steady illumination of the centre of the receptive field. This confirms Krüger & Fisher (1973), but the effect is only found in a proportion of cells. 6. The mechanism that generates peripherally evoked responses is tentatively identified with the 'rectifying subunits' postulated by Hochstein & Shapley (1976b) to account for the spatial non-linearity in the receptive fields of Y-cells. Transient (bistratified) amacrine cells are known to have many of the properties attributed to these mechanisms (Chan & Naka, 1976).

Animals↗
PubMed1976

Properties of LGN cells in kittens reared with convergent squint: a neurophysiological demonstration of amblyopia.

The spatial resolution of LGN cells has been studied in 4-5 month old kittens raised with convergent squint surgically produced in one eye at the age of 3-4 weeks. The 'sustained' cells which received inputs from the central retina of the squint eye showed significantly poorer spatial resolution (determined by the highest spatial frequency of a sinusoidal grating to which a cell responded with modulated firing) than those which received inputs from the central retina of the normal eye. The spatial resolution of cells which received inputs from the peripheral retina of the squint eye was not different from that of cells receiving inputs from the peripheral retina of the normal eye. The visual latency of 'sustained' cells which received an input from the area centralis of the squint eye was considerably lenghtned and the response showed a sluggish onset. Thus the most important clinical symptom of amblyopia, namely the reduction of foveal visual acuity, has been demonstrated in kittens raised with unilateral vonvergent squint. The results suggest that the lesion responsible for amblyopia due to squint might be a functional degeneration of the high spatial frequency tuning cells in the pathway prior to the visual cortex, i.e. in the retina or LGN.

Amblyopia↗
PubMed1976

The fine structure of lung macrophages from rhesus and squirrel monkeys, with special reference to the large numbers of mitochondria.

Alveolar macrophages from 2 species of nonhuman primates, rhesus and squirrel monkeys, were studied by electron microscopy. These macrophages seemed to differ from their counterparts in other animal species with respect to their large numbers of mitochondria. Monkey alveolar macrophages often contained crystalline material and a variety of inclusions in their cytoplasm, which did not seem to interfere with their phagocytic ability. The significance of these findings as they might relate to pulmonary infestation with mites and nematodes is discussed.

Animals↗
PubMed1975

Some considerations in the formulation of psychiatric diagnoses.

This paper attempts to show that psychiatric diagnosis depends to a significant degree on not only the patient's presenting symptoms but also on the psychiatrist's psychosocial biases. The importance of a psychiatric diagnosis is seen in terms of the potential social restrictions and prejudices that can be a consequence of a person labeled with a mental illness. Also, current treatment techniques and valid statistics for research are based on reliable and consistent psychiatric diagnoses. A study of 267 cases from a major psychiatric hospital revealed over 12 per cent discrepancy between the official discharge diagnosis and a resident's training report diagnosis that is used only for teaching purposes. This discrepancy is statistically significant and the paper attempts to elucidate some of the characteristics of the special population that had its diagnosis made less severe on discharge. Of the 267 charts surveyed, 33 patients had their diagnosis changed from a psychotic diagnosis on the resident's training report to a neurotic or characterological diagnosis on the official discharge summary. In addition, interviews were arranged with the 18 psychiatric residents who had been involved in changing the diagnosis of target group patients. The results obtained from these interviews definitely confirm that psychiatric diagnoses are changed due to social conditions unrelated to the psychopathological state. From the demographic data of the patient groups, a pattern evolved showing that men were generally more protected than women, that black males were more protected than black females, that unskilled laborers and those on the lower end of the socioeconomic scale were more protected than professionals, and that housewives were less protected than other categories. A number of conclusions were made by the authors concerning the data. The authors hope that these findings will enable other mental health workers to be more aware of their psychosocial biases that may be influencing their diagnostic skills.

Attitude of Health Personnel↗
PubMed1975

Radiology in chemical sympathectomy.

Chemical sympathectomy is an alternative to surgical sympathectomy when the patient's age or general condition precludes surgery. The indications and rationale in lower-limb arterial disease are discussed, and it is suggested that X-ray control is a valuable adjunct to the procedure.

Ganglia, Autonomic↗
PubMed1975

Differences in surface morphology of alveolar macrophages attached to glass and to millipore filters: a scanning electron microscope study.

The topography of alveolar macrophages (AM) attached to glass or to Millipore filters was scanning electron microscopy. The cells were obtained from normal and from BCG-vaccinated rabbits. Macrophages that adhered to glass tended to spread while essentially all of the cells that adhered to the Millipore filters remained rounded. The surface morphology of AM attached to Millipore filters closely resembles the morphology of these cells when viewed in situ on the alveolar wall. The use of Millipore filters to study the effect of microbial or host products on cell surface alterations of AM is discussed.

Animals↗