Spatiotemporal control of mitotic exit during anaphase by an aurora B-Cdk1 crosstalk

According to the prevailing 'clock' model, chromosome decondensation and nuclear envelope reformation when cells exit mitosis are byproducts of Cdk1 inactivation at the metaphase-anaphase transition, controlled by the spindle assembly checkpoint. However, mitotic exit was recently shown to be a function of chromosome separation during anaphase, assisted by a midzone Aurora B phosphorylation gradient - the 'ruler' model. Here we found that Cdk1 remains active during anaphase due to ongoing APC/CCdc20- and APC/CCdh1-mediated degradation of B-type Cyclins in Drosophila and human cells. Failure to degrade B-type Cyclins during anaphase prevented mitotic exit in a Cdk1-dependent manner. Cyclin B1-Cdk1 localized at the spindle midzone in an Aurora B-dependent manner, with incompletely separated chromosomes showing the highest Cdk1 activity. Slowing down anaphase chromosome motion delayed Cyclin B1 degradation and mitotic exit in an Aurora B-dependent manner. Thus, a crosstalk between molecular 'rulers' and 'clocks' licenses mitotic exit only after proper chromosome separation.

[Use of amitriptyline in attention deficit hyperactivity disorder]

We studied the action of amitriptyline (AMI) in the attention deficit hyperactivity disorder (ADHD). Twenty-five children who came to consultation for ADHD were analyzed, in two groups: the group which used AMI (n = 18) at 1.6 mg/kg/day and the group which used placebo (n = 7). Both groups were submitted to two assessments in a 30 days interval, which consisted of the evolutive neurological evolution examination (ENE) and the WISC scale subtests on numbers, drawings to be completed and the code. The results showed that the AMI produced an improvement in performance in the motor persistence tests.

[Performance of literacy and cortical brain functions in a sample of first grade students of Porto Alegre, Brazil]

Cortical brain functions are the basis of the learning process and evolutionary neurological examination (ENE) provides the level of development of the brain. The purpose of this work was to study by means of the ENE the brain functions in a representative sample of first grade students of Porto Alegre, to investigate the learning performance. An observation, analytical and transversal delineated study was performed. The random sample had 484 children. It was observed: sex, age, race, weight, height, neurological examination, ENE, performance in the number sub-tests, completing figures and codes from WISC scale and literacy learning. The items of ENE were below the expected for the age in 11.4% and 38.2% of the children: the most affected ones were the sensitivity activity and gnosias (38.2%) and the least one was motor persistence (11.4%). In psychometric tests, 40.5% of the subjects had their development in numbers below the espected, 39.0% in accomplishing figures, 71.5% in codes. Concerning literacy, 94.4% of the children learned to read and write. The neuropsychological dysfunction and malestablished laterality were a risk factor for the learning process.