The development of aggressiveness between 5 and 17 years and some parental influences on this development were analyzed using data from Germany. International studies have shown a ''camel humps'' curve, i.e., a peak of aggression of children (primarily boys) between 2 and 4 years and a second peak of antisocial or aggressive behavior of boys between 15 and 20 years, but small groups of children and adolescents were persistently aggressive. A representative longitudinal study (2,190 children and their parents) and an additional study (1,372 children and adolescents) were conducted in Germany. The hypotheses of this article are that in the data can be found (a) an U-shaped course of aggressiveness for boys and girls, but on different levels, (b) a minority of persistently aggressive children and youth, (c) influences of parental temperaments, behavioral tendencies, parenting styles and the family status on the children's aggressiveness. The results replicate roughly the ''valley'' of the U-shaped course of aggressiveness. Small groups of chronically aggressive children were found as well. Influences of parental temperaments and corresponding behavioral tendencies (internalizing and externalizing behavior), parenting styles (child-centered communication, use of violence) and the social status of the families on child aggressiveness confirmed the hypotheses. These processes were moderated by gender effects between mothers, fathers, daughters, and sons. In regard to the group of persistently aggressive young people prevention of aggression should start early in childhood and over the long term. Parent education should consider more the individual personalities of the parents, not only parenting styles.

In order to further understand the mechanisms involved in planning an aggressive act, we conducted an event-related potential (ERP) study of young men with and without a history of violence. Participants completed a competitive reaction time task (based on the Taylor aggression paradigm) against a virtual opponent. In "passive" blocks, participants were punished by the opponent when losing the trial but could not punish, when winning, whereas in "active" blocks, participants were able to punish the opponent when winning, but were not punished when losing. Participants selected punishment strength in a decision phase prior to each reaction time task and were informed whether they had won or lost in the outcome phase. Additionally, a flanker task was conducted to assess basic performance monitoring. Violent participants selected stronger punishments, especially in "active" blocks. During the decision phase, a frontal P200 was more pronounced for violent participants, whereas non-violent participants showed an enhanced frontal negativity around 300 ms. The P200 might reflect the decision to approach the opponent at a very early state, the latter negativity could reflect inhibition processes, leading to a more considerate reaction in non-violent participants. During the outcome phase, a Feedback-Related Negativity was seen in both groups. This effect was most pronounced when losing entailed a subsequent inability to retaliate. The groups did not differ in the flanker task, indicating intact basic performance monitoring. Our data suggest that the planning of an aggressive act is associated with distinct brain activity and that such activity is differentially represented in violent and non-violent individuals.

In the last 2 years we have developed a new method for determining insulin biologic activity with the help of the glucose-controlled insulin infusion system (GCIIS). Primarily this closed-loop system infuses insulin. But to prevent hypoglycemia, it can in addition, infuse glucose below a certain blood glucose minimum. This effect is used to reproduce insulin biologic activity. After subcutaneous injection of the insulin to be tested in healthy persons (not in insulin-dependent diabetic subjects), the blood glucose level falls, and this is checked by the counterregulatory glucose delivery from the apparatus. The time and intensity of glucose delivery from the GCIIS reflect the insulin effect, so that each insulin manifests its own particular biologic activity.

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This study describes the pharmacokinetics of three intermediate-acting insulin preparations, NPH porcine insulin, NPH human insulin (recombinant DNA), and "Depot-A" insulin, a mixture of 20% regular and 80% NPH human insulin from Eli Lilly and Company. Metabolic healthy normal weight volunteers were selected for the study. After overnight fasting, each test person received 0.4 U of each insulin per kg body weight injected subcutaneously in the triceps area of the arm. To prevent severe hypoglycemia, the test persons were connected to a "GCIIS Biostator" with blood glucose clamp at the 60 mg/dl level. Peripheral blood was sampled at regular intervals for glucose, insulin, and C-peptide determination. More elevated insulin levels were measured after application of both NPH human insulin and "Depot-A" insulin than after NPH porcine insulin. A more rapid decrease in the blood glucose concentration was observed after injection of both human insulin preparations than after porcine insulin. The dextrose output of the "GCIIS Biostator" was more pronounced in both human insulins than after the porcine preparation. After the injection of NPH human and NPH porcine insulin, significant differences were calculated between the concentrations of these two insulins in the blood, from the 2nd to the 10th hour (P less than 0.05-P less than 0.005) and between the dextrose output of the "GCIIS Biostator" from the 3rd to the 8.5th hour (P less than 0.05). The fall of the C-peptide concentration to the lower detection limit of the assay reflects suppression of the endogenous B-cell secretion and confirms the measure of peripheral insulin concentrations as a result of the exogenously applied insulin. Although all investigations were performed under identical experimental conditions and equal dosages of each insulin were injected, higher insulin concentrations and a stronger biologic effect, shown by larger amount of dextrose delivered, were observed in both human insulins than in porcine insulin. Why this phenomenon occurs is as yet unclear. The clamp technique used with the "GCIIS Biostator" enables establishment of the biologic profile of any insulin, and thus represents a valuable tool in comparative studies.