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In wound healing assays, a monolayer of epithelial cells is allowed to migrate onto empty surface area. When the motile cells close the artificial wound, the edge of the tissue does usually not move uniformly but characteristic fingerlike protrusions are observed. We model the collectively moving cells as a system of self-propelled particles using the Toner-Tu equations for an active fluid. A linear stability analysis of perturbations at the tissue edge reveals an instability in the disordered nonmoving state. The instability is purely due to spontaneous motility and velocity alignment between cells. It can account for finger formation in wound healing experiments.

The spontaneous motility and chemotaxis of PMNs have been investigated in 25 healthy subjects aged 69–88 years (79.04 ± 4.6) and compared with the values obtained in 25 subjects aged 17–35 years (25.6 ± 5.9). For spontaneous motility, the values were 32 ± 9 in the young subjects, in comparison with 24 ± 11 in the elderly (p < 0.05). For chemotaxis the values were 34 ± 14 in the young subjects and 25 ± 10 in the elderly (p < 0.02). A group of 8 elderly subjects received 2 g ascorbic acid daily for 1 month. Measurements of spontaneous motility and chemotaxis were conducted, and the results were compared with those obtained prior to the treatment. Neither parameter was significantly modified. Another group of 8 elderly subjects received 50 mg of levamisole daily for 3 days. This drug caused a significant increase in spontaneous motility (p < 0.0001) and chemotaxis (p < 0.05). In our experience, the elderly exhibit a decrease in spontaneous motility and chemotaxis of PMNs in comparison with those values obtained in young people. Although levamisole increased the values of both parameters, ascorbic acid did not.

These studies were performed to investigate the influence of diethyldithiocarbamate on the toxicity of amphetamine in aggregated mice. In the same mice changes in body temperature and spontaneous motility were determined. In the other experiments brain catecholamine concentrations were assayed. Diethyldithiocarbamate potentiated the toxicity of amphetamine in some experimental conditions and slightly antagonized it in others. These effects are discussed in relation to behavioral and biochemical changes observed in mice.

The effect of Psilocybin on the behavior of the baboon Papiopapio has been studied. Animal watchfulness, as estimated from the E.E.G., is enhanced within the first five minutes after injection and then is not further modified. Psilocybin induces a decrease of spontaneous motility. Conversely, the frequency of eye movements is considerably increased. This pattern might be explained by alterations of visual perception.

A new piperidine derivative, the 2-diphenylmethylpiperidine, produces already in doses of 0.001 g/kg s.c. a strong increase of the spontaneous motility of various animals. On mice it has about the same potency as d-desoxy-ephedrine and is about 3 times more potent than amphetamin. It also acts markedly antagonistic on various narcotics but has practically no peripheral sympathomimetic effects.

IN the course of the search for the hormone which results in inhibition of gastric secretion and motility after fat has entered the duodenum, the ability of duodenal extracts to inhibit the motility of denervated gastric pouches has become crucial. The presence of fat in the duodenum inhibits the spontaneous motility of Heidenhain pouches1, but many duodenal extracts which inhibit acid secretion will not do this. Extracts of duodenal mucosa containing secretin2 and even more conclusively extracts containing cholecystokinin/pancreozymin3 inhibit gastric acid secretion.