Rehearsal initiates systems memory consolidation, sleep makes it last.

After encoding, memories undergo a transitional process termed systems memory consolidation. It allows fast acquisition of new information by the hippocampus, as well as stable storage in neocortical long-term networks, where memory is protected from interference. Whereas this process is generally thought to occur slowly over time and sleep, we recently found a rapid memory systems transition from hippocampus to posterior parietal cortex (PPC) that occurs over repeated rehearsal within one study session. Here, we use fMRI to demonstrate that this transition is stabilized over sleep, whereas wakefulness leads to a reset to naïve responses, such as observed during early encoding. The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.

Fast track to the neocortex: A memory engram in the posterior parietal cortex.

Models of systems memory consolidation postulate a fast-learning hippocampal store and a slowly developing, stable neocortical store. Accordingly, early neocortical contributions to memory are deemed to reflect a hippocampus-driven online reinstatement of encoding activity. In contrast, we found that learning rapidly engenders an enduring memory engram in the human posterior parietal cortex. We assessed microstructural plasticity via diffusion-weighted magnetic resonance imaging as well as functional brain activity in an object-location learning task. We detected neocortical plasticity as early as 1 hour after learning and found that it was learning specific, enabled correct recall, and overlapped with memory-related functional activity. These microstructural changes persisted over 12 hours. Our results suggest that new traces can be rapidly encoded into the parietal cortex, challenging views of a slow-learning neocortex.

Decoding material-specific memory reprocessing during sleep in humans.

Neuronal learning activity is reactivated during sleep but the dynamics of this reactivation in humans are still poorly understood. Here we use multivariate pattern classification to decode electrical brain activity during sleep and determine what type of images participants had viewed in a preceding learning session. We find significant patterns of learning-related processing during rapid eye movement (REM) and non-REM (NREM) sleep, which are generalizable across subjects. This processing occurs in a cyclic fashion during time windows congruous to critical periods of synaptic plasticity. Its spatial distribution over the scalp and relevant frequencies differ between NREM and REM sleep. Moreover, only the strength of reprocessing in slow-wave sleep influenced later memory performance, speaking for at least two distinct underlying mechanisms between these states. We thus show that memory reprocessing occurs in both NREM and REM sleep in humans and that it pertains to different aspects of the consolidation process.

[Glycemic control and cardiovascular benefit: What do we know today?]. / Blutzucker-Senkung und kardiovaskulärer Vorteil: Was wissen wir heute?

It is still a much debated question whether antidiabetic therapy to target normal glycated hemoglobin levels would reduce cardiovascular events in patients with advanced type 2 diabetes. New findings result from ACCORD, ADVANCE and VADT. These trials reveal that microvascular and macrovascular effects of intensive glucose lowering have to be considered separately: Glycemic control convincingly demonstrated to have a protective impact on microvascular complications, especially nephropathy. However, macrovascular benefits remain doubtful in these megatrials and have to be considered in connection with the individual global risk. On the other hand, the Diabetes Intervention Study (DIS) and UKPDS 10-year follow-up results yielded better cardiovascular outcomes for those patients who received intensive glucose-lowering therapy very early after diabetes diagnosis, but the favourable influences did not manifest until a time period of 1 - 2 decades. For the first time, the cardiovascular benefit of an antidiabetic substance (pioglitazone) could be verified in the large-scale outcome-trial PROactive for patients with advanced diabetes and multiple manifestations of macroangiopathy. The results provide strong support for a beneficial influence on macrovascular complications just under 3 years of treatment. Nevertheless, the positive findings did not result from better glycemic control, but from the complexity of effects of PPARgamma agonist pioglitazone on insulin resistance, lipoprotein spectrum, blood pressure, endothelial function and biomarkers of subclinical inflammation. It is obvious that we need to integrate such pleiotropic effects on metabolic syndrome and cardiovascular disease to improve the quality of drug-therapy decisions. This, in turn, requires a growing body of evidence from large, long-term outcome trials - but appropriate data are still unavailable for the vast majority of antidiabetic drugs.

Sudden improvement of insulin sensitivity related to an endodontic treatment.

BACKGROUND: Inflammation contributes to the pathogenesis of diabetes. A reciprocal relationship exists between diabetes and chronic periodontitis. This report describes the effects of an acute focal dental inflammation and subsequent endodontic treatment on the required insulin dosage of a 70-year-old man who had moderately controlled diabetes. METHODS: Following an exacerbation of a combined endodontic-periodontic (endo-perio) lesion of tooth #3, the patient noticed a sudden increase in his insulin demand. After 3 weeks, the required dosage was approximately 100% greater. In association with hyperglycemic incidents, he reported a prickling sensation in this tooth. The radiograph showed circular bone loss around the tooth. RESULTS: Just 1 day after the root-canal preparation, the insulin need decreased to approximately 50% of that required prior to treatment. Subsequently, an incision and systemic antibiotics were necessary because of the formation of a periodontal abscess. The insulin demand remained low despite this complication. Forty days after endodontic treatment, the insulin dosage was at a level comparable to that taken 4 weeks before the root-canal preparation. CONCLUSIONS: This clinical case revealed a highly relevant correlation between insulin resistance and a local dental inflammation. To avoid an increase in insulin resistance, it seems important to attend to radically non-vital teeth as well as any other dental inflammation in diabetic patients.

Pregnancy outcome and recurrence after conservative laparoscopic surgery for borderline ovarian tumors.

BACKGROUND: The aim of this study was to evaluate the safety and efficacy of conservative laparoscopic management of borderline ovarian tumors, and to assess pregnancy outcome and recurrence after fertility-sparing surgery. METHODS: From 1995 to 2005, 43 patients of reproductive age presented with adnexal mass, which was subsequently diagnosed as a borderline tumor of the ovary. These patients were treated by conservative laparoscopic surgery, with intraoperative staging of the disease. Patients were evaluated every 3 months for the first 2 years, and then every 6 months thereafter, to determine the best modality for following patients after conservative surgery. RESULTS: Three (7%) patients developed a recurrence after conservative treatment. Among the 43 patients who had conservative surgery, 21 (49%) became pregnant during the follow-up period; 12 (57%) conceived spontaneously, and the remaining 9 (43%) patients underwent caesarean section. CONCLUSIONS: In our opinion, conservative laparoscopic treatment of borderline ovarian tumors is an appropriate and reasonable therapeutic option for young women with low-stage disease who wish to preserve their childbearing potential, because the fertility results are encouraging. Recurrence can be noted after this type of treatment, but the cases of recurrent disease can be detected with close follow-up and treated accordingly. Careful selection of candidates for this kind of treatment is, of course, necessary, and close follow-up is required.

Intracranial pressure patterns after endoscopic third ventriculostomy. Preliminary experience.

BACKGROUND: Endoscopic Third Ventriculostomy (ETV) has become the treatment of choice for non-communicating hydrocephalus as it is able to couple high success rate (60-80%) with rare complications (about 5%). Nevertheless, which is the best postoperative care standard and whether or not it is possible to predict the success of the procedure is still discussed. Traditional neuro-imaging techniques show several limitations in the early postoperative period. Indeed, a decrease of the ventricular size is often minimal and not visible before three weeks, while, MRI visualization of a flow void signal through the third ventricle floor, seems to have a significant incidence of false positives. The use of postoperative ICP measurement after ETV has been suggested as a valid monitoring method, mostly in the early postoperative period. In previously unpublished data the authors observed the existence of different ICP patterns following ETV. This finding prompted the authors to search for a relationship among ICP patterns, stoma functioning and prediction of success. METHOD: At our institution 26 consecutive patients affected by obstructive triventricular hydrocephalus underwent ETV. Among them there were 11 primitive aqueductal stenosis (AS), 5 shunt malfunctions, 2 third ventricle mass, 3 intraventricular cysts, and 5 patients with different lesions (1 quadrigeminal cistern arachnoidal cyst, 1 pineal region mass, 2 tectal tumours, and 1 supracerebellar abscess) compressing the aqueduct of Sylvius from outside named " ab estrinseco" aqueductal stenosis. All patients underwent postoperative Intra Cranial Pressure (ICP) monitoring by means of a ventricular catheter. FINDINGS: Transient ICP rises of any grade, mostly responsive to periodical liquoral subtractions, occurred shortly after ETV in as many as 50% of our patients. No major complications occurred. The effect of ETV on ICP trend was found to be variable among groups of patients thus identifying different ICP patterns. Patients with ab estrinseco Sylvian aqueduct compression showed the best effect on ICP, whilst, patients with intraventricular mass lesions causing triventricular hydrocephalus and shunt-dependent patients, revealed a clear trend to develop a more severe intracranial hypertension after ETV. CONCLUSIONS: Patients with shunt malfunction and patients with intraventricular mass lesions, showing a more pronounced trend to develop severe intracranial hypertension after ETV, should always be considered for postoperative ICP monitoring in order to detect and, eventually, treat any ICP rises which may occur. Unfortunately, it is still difficult to assign a predictive value to the different postoperative ICP patterns. The authors encourage postoperative ICP monitoring in all patients in order to define all the possible ICP patterns following ETV.

Intracranial pressure monitoring after endoscopic third ventriculostomy: an effective method to manage the 'adaptation period'.

Endoscopic third ventriculostomy (ETV) has become the treatment of choice for non-communicating hydrocephalus. Nevertheless, which technique should be considered of choice to identify features correlating with the failure of an endoscopic procedure and which is the optimal postoperative period care standard are still a matter of debate. Traditional neuroimaging techniques have several limitations in assessing the success of the procedure mostly in the early postoperative period. Indeed, a decrease in the ventricular size is often minimal and not visible before 3-4 weeks. MRI, able to detect the presence of a flow void signal through the third ventricle floor, has been reported to have a significantly high incidence of false positives. In our experience, the continuous measuring of intracranial pressure (ICP) by means of a ventricular catheter has been of great help in verifying the correct functioning of the communication between the ventricle and the subarachnoidal spaces during the first postoperative days. Furthermore, ICP monitoring allowed us to safely deal with the intracranial hypertension that may occur shortly after ETV.

High resolution multi-temperature sensors for biomedical application.

A temperature sensor array was designed in order to study local temperature variations and temperature gradients in biological samples. The sensor probe was inserted in the optical cortex of rabbits in order to study temperature changes during normal brain activity as well as under artificial ventilation conditions. Temperature sensitive areas of 0.14 mm x 0.1 mm are arranged in a row with interdistances of 0.4 mm yielding high spatial resolution. A temperature resolution of 0.1 mK and a 90% response time of maximum 3 milliseconds was obtained utilizing the high temperature dependence of 2%/K of the conductivity of vacuum evaporated germanium films. The sensor is passivated by a 1 micron thick PECVD-silicon nitride layer and can be placed on glass-, alumina- and polymer substrates. For brain tissue studies, in order to minimize tissue damage the temperature sensors were placed on a 0.1 mm thick needle-shaped glass substrate. A sensor element mounted on a glass substrate and immersed in water showed a self heating of less than 5 mK due to the applied measurement current of 2.1 microA.

Space occupying contusions of cerebral lobes after closed brain injury: considerations about 51 cases.

Fifty one cases of space occupying contusions of the brain have been treated between 1967 and 1974. These represented 2.4% of all head injuries. Forty four were surgically treated and only clinically. The total mortality was 50.9% being 91.4% in patients above 50 years of age and 41% in patients below 50. In 66.6% of patients the lesions were localized in the temporal lobes, and two patients had localized cerebellar contusions. Surgery was performed in 44 patients. There were 13 craniectomies and 31 craniotomies. The operative mortality was 54.5%. Mortality was 65.2% in patients operated on within 24 hours of injury, and 12.5% in those operated on more than 72 hours after trauma. Twenty five patients (20 treated surgically and 5 managed clinically) were examined one year after injury. Eighty four percent were in either good or excellent condition.