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Biomedical subjects

M D London

Publications and source records attributed to M D London.

5 recordsLinked to original sources

Fibrous dysplasia. An analysis of options for treatment.

The results of treatment of sixty-five symptomatic lesions in forty-three patients who had fibrous dysplasia were reviewed. For fourteen (93 per cent) of the fifteen times that a lesion in the upper extremity was treated non-operatively, the result was satisfactory. These results were independent of the patient's age when first seen. In contrast, in the lower extremity, the results were highly dependent on the age of the patients at the time of the initial presentation of symptoms. In patients who were eighteen years old or older, eight (88 per cent) of the nine times that a lesion involving the lower extremity had closed treatment and both times that a lesion was treated with curettage and bone-grafting, the result was satisfactory. The results of these modalities of treatment in patients who were less than eighteen years old were discouraging. Twenty-eight (88 per cent) of the thirty-two times that closed treatment was used and twenty-five (81 per cent) of the thirty-one times that curettage and bone-grafting was used, the result was unsatisfactory. However, after eighteen (86 per cent) of the twenty-one times that a lesion in the lower extremity was treated by internal fixation in a patient who was less than eighteen years old, there was a satisfactory outcome. We concluded that closed treatment of a symptomatic lesion in the upper extremity generally provides satisfactory results. In patients who are less than eighteen years old, neither closed treatment nor curettage and bone-grafting is adequate treatment for a symptomatic lesion in the lower extremity. Internal fixation should be strongly considered in these young patients.

Adolescent↗

The effect of activation versus inhibition of feedback on perceived control of EEG activity.

This study explores a model in which perceived control is affected by multiple sources of feedback at three different stages of the control sequence--person, response, and outcome. Behavior that enhances feedback is termed activation, while behavior that diminishes feedback is termed inhibition. The study tests the hypothesis that activation at any stage of the sequence leads to greater perceived control than inhibition. Eighty subjects increased or decreased their brain-wave activity (EEG) by making a tone go either on or off, using either an active or a passive strategy. Following 10 60-second trials, subjects rated their perception of control over their EEG activity. The hypothesis that making a tone go on (activation of the outcome) leads to a greater perception of control than making the tone go off (inhibition of the outcome) was confirmed only when subjects decreased their EEG activity. Perceived control was not significantly correlated with actual control, supporting the expectation that they are separately mediated. The results did not support the hypothesis that increasing EEG activity or using an activity strategy would lead to a greater perception of control than decreasing EEG or using a passive strategy. These findings are interpreted as evidence that attention to feedback may be necessary for the predicted bias in perceived control to occur, and that activation and inhibition should be operationalized as the absolute presence versus absence of feedback in testing the hypothesis for the first two stages of control.

Adolescent↗

Progression of thermal injury: a morphologic study.

The events that participate in the local pathophysiology of a burn would have not been completely described. This study defines the sequential morphologic changes following untreated partial-thickness burns. Guinea pigs received partial-thickness scald burns by 75 degrees C water immersion for 10 seconds. Skin samples were then obtained at 2, 8, 24, and 96 hours after the burn and examined by light and electron microscopy. A definite progression of the thermal injury was found, with maximum tissue destruction occurring 8 hours after the burn. At 24 hours after the burn, some improvement in the burn wound was noted, especially in the dermal microvasculature. At 96 hours, the damaged epidermis sloughed, exposing a dermis that contained areas resembling microabscesses.

Animals↗

Cooling the burn wound to maintain microcirculation.

To evaluate the effect which cooling of burn wounds has upon dermal microvascular circulation, standard 10% BSA dorsal guinea-pig scald burns were created. In treated animals, the dorsal burned region was immersed in a circulating ice-water bath (0-3 degrees C) for 30 minutes at various time intervals postburn (10,20,30, and 60 minutes after scald). India-ink perfusion was used to determine the level of dermal vessel patency at 2, 4, 8, 24, 72, and 96 hours after burning. By 96 hours, significant differences could be seen in animals cooled 10, 20, or 30 minutes after burning. Those not treated until 60 minutes after burning had dermal perfusion essentially the same as control animals. 133Xe dermal washout studies were performed at 8 and 24 hours and corroborated these findings. Grossly, burn wounds cooled by 30 minutes after burn had markedly better healing than control animals and animals cooled 60 minutes after burning. We believe these data support the early use of cold water treatment of partial-thickness burn wounds, as demonstrated in this experimental study.

Animals↗