[Digital reconstruction].

A series of experiments are described in which magnitude estimates of the perceived size of steel balls were made when the balls were actively rolled between the fingertip and several other body sites (thumb, thenar eminence, forearm). This movement, called scripting, involves actively moving an object by a touching surface over another surface of the body which is passively being touched. We define this active/passive activity as "intra-active touch" and the results show that the perceptual size of the balls is dependent upon the body part passively being activated. An additional series of experiments decoupled the actively generated and passively received tactile information by having subjects either perform the scripting on another individual's body site or by having the other individual roll the balls on the subject's various sites. The latter experiments showed that the passive body can contribute to the overall impression of the size of the balls, but only when the intra-active touching involved the glabrous skin of the hands. Intra-active touch between the active finger and the passively touched hairy skin of the forearm showed no effect of the touched surface on the perceived size of the balls. The results suggest that the mechanisms of intra-active touch are different when glabrous skin activates glabrous skin than when glabrous skin activates hairy skin.

Fingers↗

PubMed2004

Symmetrical peripheral gangrene.

Symmetrical peripheral gangrene (SPG), seen in a wide variety of medical conditions presents as symmetrical gangrene of two or more extremities without large vessel obstruction or vasculitis. Fingers, and toes (rarely nose, ear lobes or genitilia) are affected. It may manifest unpredictably in conditions associated with sepsis, low output states, vasospastic conditions, myeloproliferative disorders or in hyperviscosity syndrome. It carries a high mortality rate with a very high frequency of multiple limb amputations in survivors. Disseminated intravascular coagulation (DIC) is seen in majority of cases of SPG. A more or less stereotyped clinical picture of SPG in spite of ever widening aetiological spectrum is suggestive of DIC as the final common pathway of its pathogenesis. Early recognition of acrocyanosis, quick reversal of DIC, effective management of the underlying condition, haemodynamic stabilization and (perhaps) anticoagulation with low dose heparin (300-500 iu/hour) may be helpful in arresting the progression of pre-gangrenous changes to frank gangrene. Vasopressors such as dopamine should be used judiciously in the presence of DIC. Development of acrocyanosis and increase in serum lactate levels may be indicative of impending SPG and the imperative need to treat DIC as well as the underlying condition.

Fingers↗