The Histopathological Growth Pattern of Colorectal Liver Metastases Impacts Local Recurrence Risk and the Adequate Width of the Surgical Margin.

BACKGROUND: The histopathological growth pattern (HGP) of colorectal liver metastases (CLM) has been associated with prognosis. This study was designed to elucidate if the HGP is associated with local recurrence risk and impacts the adequate width of surgical margin. METHODS: All consecutive patients resected for CLM in 2018-2019 were considered. HGP was prospectively classified as follows: desmoplastic, pushing, and replacement. Surgical margin was classified as follows: R0 (margin ≥ 1 mm), R1vasc (0-mm margin, tumor detachment from intrahepatic vessels), and R1par (tumor exposure along transection plane). R0 resections were further distinguished in R0min (1-mm margin) and R0wide (> 1-mm margin). RESULTS: A total of 340 resection areas in 136 patients were analyzed (70 R0min, 143 R0wide, 31 R1vasc, 96 R1par). HGP was desmoplastic in 26 cases, pushing in 221, and replacement in 93. Thirty-six local recurrences occurred (11%, median follow-up 21 months): 1 after R0wide, 4 after R0min, 3 after R1vasc, and 28 after R1par resection. In R1par group, local recurrence rate was high independently of HGP (29%). In R1vasc and R0min groups, local recurrence risk was higher in the replacement group (R1vasc: 29% vs. 4% if pushing/desmoplastic; R0min: 11% vs. 4%). In R0wide group, local recurrence risk was low for all HGP ( < 1%). Independent predictors of local recurrence were replacement HGP (odds ratio = 1.654, P = 0.036), and R1par resection (odds ratio = 57.209, P < 0.001 vs. R0). CONCLUSIONS: Replacement HGP is associated with an increased risk of local recurrence. In these patients, a wide surgical margin should be pursued, because R1vasc and R0min resections could be insufficient. R1par resection is inadequate, independently of the HGP.

Laparoscopic and open liver resection for hepatocellular carcinoma with Child-Pugh B cirrhosis: multicentre propensity score-matched study.

BACKGROUND: Laparoscopic liver resection for hepatocellular carcinoma (HCC) in Child-Pugh A cirrhosis has been demonstrated as beneficial. However, the role of laparoscopy in Child-Pugh B cirrhosis is undetermined. The aim of this retrospective cohort study was to compare open and laparoscopic resection for HCC with Child-Pugh B cirrhosis. METHODS: Data on liver resections were gathered from 17 centres. A 1 : 1 propensity score matching was performed according to 17 predefined variables. RESULTS: Of 382 available liver resections, 100 laparoscopic and 100 open resections were matched and analysed. The 90-day postoperative mortality rate was similar in open and laparoscopic groups (4.0 versus 2.0 per cent respectively; P = 0.687). Laparoscopy was associated with lower blood loss (median 110 ml versus 400 ml in the open group; P = 0.004), less morbidity (38.0 versus 51.0 per cent respectively; P = 0.041) and fewer major complications (7.0 versus 21.0 per cent; P = 0.010), and ascites was lower on postoperative days 1, 3 and 5. For laparoscopic resections, patients with portal hypertension developed more complications than those without (26 versus 12 per cent respectively; P = 0.002), and patients with a Child-Pugh B9 score had higher morbidity rates than those with B8 and B7 (7 of 8, 10 of 16 and 21 of 76 respectively; P < 0.001). Median hospital stay was 7.5 (range 2-243) days for laparoscopic liver resection and 18 (3-104) days for the open approach (P = 0.058). The 5-year overall survival rate was 47 per cent for open and 65 per cent for laparoscopic resection (P = 0.142). The 5-year disease-free survival rate was 32 and 37 per cent respectively (P = 0.742). CONCLUSION: Patients without preoperative portal hypertension and Child-Pugh B7 cirrhosis may benefit most from laparoscopic liver surgery.

Health and social conditions of children living in disadvantaged neighborhoods in the city of Rome, Italy.

OBJECTIVE: The number of children living in socio-economically disadvantaged neighborhoods in developed countries is constantly growing, resulting in important implications for children's development, physical and psychological health and increased future disparities. In this study, we explored several key elements of children living in poor neighborhoods, such as demographic characteristics, access to public health assistance and school, and availability of housing and basic hygienic conditions. PATIENTS AND METHODS: The study included 711 children aged 0-17 years referring to primary care services in the suburbs of the city of Rome, Italy. RESULTS: Most children were born in Italy, while almost none of their parents were. Nearly 60% of the children did not have access to basic pediatric care, causing possible misdiagnosis and delayed treatment for acute and chronic conditions. A smaller percentage of the children did not have access to basic housing (8%) and hygienic facilities, such as heating, running water, and refrigerator (3.2%), leading to malnutrition, isolation and poor physical and psychological development. CONCLUSIONS: This study confirms a critical condition for children living in disadvantaged neighborhoods, whose vulnerability is further worsened by the limited access to paediatric health assistance and, in some cases, to basic facilities with a severe impact on their physical and psychological development.

Multicentre evaluation of case volume in minimally invasive hepatectomy.

BACKGROUND: Surgical outcomes may be associated with hospital volume and the influence of volume on minimally invasive liver surgery (MILS) is not known. METHODS: Patients entered into the prospective registry of the Italian Group of MILS from 2014 to 2018 were considered. Only centres with an accrual period of at least 12 months and stable MILS activity during the enrolment period were included. Case volume was defined by the mean number of minimally invasive liver resections performed per month (MILS/month). RESULTS: A total of 2225 MILS operations were undertaken by 46 centres; nine centres performed more than two MILS/month (1376 patients) and 37 centres carried out two or fewer MILS/month (849 patients). The proportion of resections of anterolateral segments decreased with case volume, whereas that of major hepatectomies increased. Left lateral sectionectomies and resections of anterolateral segments had similar outcome in the two groups. Resections of posterosuperior segments and major hepatectomies had higher overall and severe morbidity rates in centres performing two or fewer MILS/month than in those undertaking a larger number (posterosuperior segments resections: overall morbidity 30·4 versus 18·7 per cent respectively, and severe morbidity 9·9 versus 4·0 per cent; left hepatectomy: 46 versus 22 per cent, and 19 versus 5 per cent; right hepatectomy: 42 versus 34 per cent, and 25 versus 15 per cent). CONCLUSION: A volume-outcome association existed for minimally invasive hepatectomy. Complex and major resections may be best managed in high-volume centres.

ANTECEDENTES: Los resultados quirúrgicos pueden estar relacionados con el volumen de casos del hospital, pero no se conoce la influencia en la cirugía mínimamente invasiva del hígado (minimally­invasive liver surgery, MILS). MÉTODOS: Se incluyeron los pacientes registrados en el registro prospectivo del grupo italiano de MILS desde 2014 a 2018. Solo se consideraron centros con extensión de ≥ 12 meses y actividad estable de MILS durante el periodo de reclutamiento. El volumen de casos se definió como el número de MILS efectuado por mes. RESULTADOS: Se llevaron a cabo un total de 2.225 MILS en 46 centros, 9 de ellos con > 2 MILS/mes (n = 1.376 pacientes) y 37 centros con ≤ 2 MILS/mes (n = 849). La proporción de resecciones de segmentos anterolaterales disminuyó con el volumen de casos, mientras que la proporción de hepatectomías mayores aumentó. Los resultados para ambos grupos fueron similares en las seccionectomías lateral izquierda y en las resecciones del segmento anterolateral. Las resecciones del segmento posterosuperior y las hepatectomías mayores presentaron tasas más altas de morbilidad global y morbilidad grave en centros que realizaban ≤ 2 MILS/mes que en los que realizaban > 2 MILS/mes (resecciones del segmento posterosuperior, morbilidad global 30,4 versus 18,7%, morbilidad grave 9,9 versus 4,0%; hepatectomía izquierda, 46,2 versus 22,0%, 19,2 versus 5,5%; hepatectomía derecha, 41,7 versus 33,8%, 25,0 versus 14.9%). CONCLUSIÓN: Se observó una asociación volumen­resultado para la resección hepática mínimamente invasiva. Las resecciones complejas y mayores se pueden manejar mejor en centros de gran volumen.

Optimization of the use of a pharmaceutical grade xeno-free medium for in vitro expansion of human mesenchymal stem/stromal cells.

Human bone marrow-derived mesenchymal stem/stromal cells (hMSCs) are considered promising therapeutic agents in the field of cell therapy and regenerative medicine, mainly due to their relative facility to be isolated, multi-differentiation potential, and immunomodulatory role. However, their application in clinics requires a crucial step of in vitro expansion. Most of the protocols for hMSCs in vitro culture use foetal bovine serum as medium supplement that, being from animal origin, presents several safety concerns and may initiate xenogeneic immune responses after cells transplantation. This work reports the optimization of a pharmaceutical-grade xeno-free strategy for hMSCs in vitro expansion based on the supplementation of basal medium with a pharmaceutical-grade human plasma-derived supplement for cell culture (SCC) and 2 human growth factors (bFGF and TGFß1), plus a coating of human plasma fibronectin (Fn). After 4 weeks in culture, this strategy improves hMSCs expansion yield about 4.3-fold in comparison with foetal bovine serum supplementation and 4.5-fold compared with a commercially available xeno-free medium. hMSCs expanded in SCC-based formulation maintained their phenotype and differentiation capacity into osteogenic, adipogenic, and chondrogenic lineages, without alterations in cell karyotype. Overall, the SCC-based medium appears to be an excellent alternative for the xeno-free expansion of hMSCs as therapeutic agents for clinical applications.

Xeno-Free Strategies for Safe Human Mesenchymal Stem/Stromal Cell Expansion: Supplements and Coatings.

Human mesenchymal stem/stromal cells (hMSCs) have generated great interest in regenerative medicine mainly due to their multidifferentiation potential and immunomodulatory role. Although hMSC can be obtained from different tissues, the number of available cells is always low for clinical applications, thus requiring in vitro expansion. Most of the current protocols for hMSC expansion make use of fetal bovine serum (FBS) as a nutrient-rich supplement. However, regulatory guidelines encourage novel xeno-free alternatives to define safer and standardized protocols for hMSC expansion that preserve their intrinsic therapeutic potential. Since hMSCs are adherent cells, the attachment surface and cell-adhesive components also play a crucial role on their successful expansion. This review focuses on the advantages/disadvantages of FBS-free media and surfaces/coatings that avoid the use of animal serum, overcoming ethical issues and improving the expansion of hMSC for clinical applications in a safe and reproducible way.

Advanced neuroimaging to quantify myelin in vivo: Application to mild TBI.

BACKGROUND: Difficulty providing accurate diagnosis and prognosis, especially after mild forms of traumatic brain injury (TBI), has increased efforts to detect changes in white matter microstructure using advanced neuroimaging techniques. Although methods such as diffusion tensor imaging (DTI) have greatly increased knowledge of white matter changes resulting from TBI, several shortcomings limit the utility of these techniques particularly when applied to populations with mild TBI (mTBI) history. In vivo imaging of myelin may be particularly well suited to detect changes in white matter microstructure resulting from mTBI. REVIEW: This manuscript will briefly review the animal and histological data supporting the important role of myelin following TBI, contributions and shortcomings of the use of diffusion tensor imaging (DTI) in mild TBI and the utility of multi-component relaxometry (MCR) techniques as a method for improved visualizing of white matter microstructural integrity in myelin. CONCLUSION: The use of MCR-based techniques has potential as a clinical and research tool to assess and track changes in myelin as well as the common behavioural changes such as slowed processing speed following TBI.

Drop-out between the two liver resections of two-stage hepatectomy. Patient selection or loss of chance?

BACKGROUND: Two-stage hepatectomy (TSH) is the present standard for multiple bilobar colorectal liver metastases (CLM), but 25-35% of patients fail to complete the scheduled procedure (drop-out). To elucidate if drop-out of TSH is a patient selection (as usually considered) or a loss of chance. METHODS: All the consecutive patients scheduled for a TSH at the Paul Brousse Hospital between 2000 and 2012 were considered. TSH patients were matched 1:1 with patients receiving a one-stage ultrasound-guided hepatectomy (OSH) at the Humanitas Research Hospital in the same period. Matching criteria were: primary tumor N status; timing of CLM diagnosis; CLM number and distribution into the liver. RESULTS: Sixty-three pairs of patients were analyzed. Demographic and tumor characteristics were similar (median 7 CLM), except for more chemotherapy lines and adjuvant chemotherapy in TSH. Drop-out rate of TSH was 38.1% (0% of OSH). The two groups had similar R0 resection rate (19.0% OSH vs. 15.9% TSH). OSH and completed TSH had similar five-year survival (from CLM diagnosis 49.8% vs. 49.7%, from liver resection 36.1% vs. 44.3%), superior to drop-out (10% three-year survival, p < 0.001). OSH and completed TSH had similar recurrence-free survival (at three years 21.7% vs. 20.5%) and recurrence sites. The completion of resection (drop-out vs. OSH/completed TSH) was the only independent prognostic factor (p = 0.003). CONCLUSIONS: Drop-out of TSH could be a loss of chance rather than a criteria for patient selection. "Unselected" OSH patients had the same outcomes of selected patients who completed TSH. A complete resection is the main determinant of prognosis.

Realdo Colombo's "De Re Anatomica": the renaissance origin of the term "placenta" and its historical background.

Over the centuries, great interest has been devoted to the placenta and to its highly symbolic significance. The Renaissance represented the age of historical and cultural transition between classical and modern scientific paradigms. In the medical setting, Realdo Colombo represents one of the protagonists of this revolution. In his masterpiece, "De Re Anatomica", he revolutionized the former medical perspective. We present a passage from this book, which carries invaluable information on the Renaissance viewpoint on pregnancy and placental biology. The connections between Colombo's theories and the previous medical tradition are also analysed.

Intraoperative ultrasonographic detection of communicating veins between adjacent hepatic veins during hepatectomy for tumours at the hepatocaval confluence.

BACKGROUND: The presence of communicating veins between adjacent hepatic veins may allow parenchyma-sparing hepatectomy. Taking advantage of improvements in ultrasound technology, such as e-flow modality, a study of the presence of communicating veins was conducted in patients with hepatic tumours at the caval confluence. METHODS: Consecutive patients undergoing surgery between October 2007 and December 2009 for hepatic tumours in contact with or invading a hepatic vein at its caval confluence were included. Communicating vein mapping by means of e-flow intraoperative ultrasonography (EF-IOUS) was carried out. RESULTS: A total of 20 patients were enrolled. Communicating veins between adjacent hepatic veins or with the inferior vena cava were detected in 16 patients. The median number of communicating veins was 1 (range 0-5). The total number of lesions removed was 126 (range 1-46). In 11 of 12 patients requiring resection of a hepatic vein, communicating veins enabled a parenchyma-sparing procedure to be performed. No patient had a formal major hepatectomy. There was no postoperative mortality or major morbidity. CONCLUSION: EF-IOUS estimation of the frequency of communicating veins between adjacent hepatic veins suggests that such veins are common. This may facilitate parenchyma-sparing procedures in patients with hepatic tumours encroaching on major hepatic veins.

Neuroprotective effect of simvastatin in stroke: a comparison between adult and neonatal rat models of cerebral ischemia.

Statins, the most widely used lipid lowering drugs, have been demonstrated to play a protective role in stroke. Animal studies confirmed the observations obtained in clinical trials and provided additional data on the putative mechanism/s of action underlying this beneficial effect. We have shown that simvastatin reduced the size of the infarct to a different extend, according to the animal model used. Indeed, in the rat neonatal model of hypoxia/ischemia simvastatin affords protection only when is administered before the ischemic insult. In contrast, in adult rats bearing middle cerebral artery occlusion, simvastatin exerted its beneficial effect on brain injury when injected for 3 days either before or after induction of ischemia. Studies carried out to determine the therapeutic window of simvastatin demonstrated that the protective effect is observed after a single dose and when the drug is administered within 3-6 hours after ischemia. Simvastatin-dependent activation of eNOS has been claimed to be one of the main mechanisms responsible for neuroprotection. This hypothesis is confirmed in the adult animal model where eNOS is activated by either pre- or post- simvastatin treatment but is not supported by the data obtained in the neonate where eNOS activity is not affected by drug treatment. These observations suggest that the protective effect of simvastatin on stroke may be mediated by multiple mechanisms as can be expected by its pleiotropic effects.

Multiexponential T2-relaxation analysis in cerebrally damaged rats in the absence and presence of a gadolinium contrast agent.

An analysis of the multiexponential relaxation of transverse nuclear magnetization with and without a gadolinium-based paramagnetic contrast agent in spontaneously hypertensive stroke-prone rats (SHR-SP) and in the rat model of ischemia induced by middle cerebral artery occlusion is described. From the multiexponential relaxation, the presence of two T(2) relaxation times in the range of 0.03-0.5 s, T(2A) (shortest) and T(2B) (longest), with very different relative weights (respectively, A and B), is evidenced. In our models of cerebral damage, the changes in A and B were more evident than those in T(2A) and T(2B). The two T(2) values were interpreted as belonging to water molecules in two different compartments; therefore, the difference between the damaged and normal regions revealed by means of standard T(2)-weighted images is suggested to be due to a different water distribution in the two compartments, rather than different T(2)'s. The T(2) relaxation in the SHR-SP stroke model is analyzed for the first time using a multiexponential method. The power of a detailed analysis of MRI relaxation times is confirmed by the correspondence between the revealed changes in T(2A), T(2B), A and B, and the known T(2)W and DWI results about blood-brain barrier functionality.

New therapeutic strategies in perinatal stroke.

Perinatal stroke represents an important cause of severe neurological deficits that span the individual's lifetime, including delayed mental and motor development, epilepsy and major cognitive deficits. Most strokes occurring in term births, infants and children can be caused by thromboembolism from intracranial and extracranial vessels and are associated with a variety of risk factors such as birth asphyxia, cardiac diseases, blood disorders, maternal disorders, trauma. Animal models of perinatal stroke have been developed to examine the nature and the time course of the events occurring after the ischemic insult and the possible therapeutic strategies useful in reducing ischemic damage. The present article addresses the potential pharmacological treatments targeting the inflammatory process and apoptotic cell death, with a specific emphasis on the emerging role of statins as neuroprotective agents in perinatal stroke. As a prelude, we will also review advances in our understanding on the mechanisms underlying the hypoxic-ischemic reperfusion injury in the newborn.

The closest living relatives of land plants.

The embryophytes (land plants) have long been thought to be related to the green algal group Charophyta, though the nature of this relationship and the origin of the land plants have remained unresolved. A four-gene phylogenetic analysis was conducted to investigate these relationships. This analysis supports the hypothesis that the land plants are placed phylogenetically within the Charophyta, identifies the Charales (stoneworts) as the closest living relatives of plants, and shows the Coleochaetales as sister to this Charales/land plant assemblage. The results also support the unicellular flagellate Mesostigma as the earliest branch of the charophyte lineage. These findings provide insight into the nature of the ancestor of plants, and have broad implications for understanding the transition from aquatic green algae to terrestrial plants.

Simvastatin protects against long-lasting behavioral and morphological consequences of neonatal hypoxic/ischemic brain injury.

BACKGROUND AND PURPOSE: Recent studies suggest that statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) not only reduce the incidence of stroke by lowering cholesterol levels but may also exert neuroprotective effects via a mechanism not related to their lipid-lowering effect. Despite the growing body of evidence, however, the neuroprotective effect of statins in stroke is still controversial. Herein, we studied whether a prophylactic administration of simvastatin (Sim) provides significant protection against brain damage, and we sought to determine its long-lasting behavioral consequences in a neonatal model of hypoxia/ischemia. METHODS: Newborn male rats were injected daily from postnatal days 1 to 7 with activated Sim (20 mg/kg) or an equivalent volume of vehicle. On postnatal day 7, the rats were subjected to ligation of the right common carotid artery, followed by 3 hours of hypoxia or by sham operation. The neuroprotective effect of Sim was evaluated after the rats had achieved adulthood by using a battery of behavioral tests and histological analysis. RESULTS: Sim-treated ischemic rats performed the circular water maze, the radial arm maze, and the multiple-choice water maze significantly better than did vehicle-treated ischemic rats. Furthermore, in contrast to the ischemic rats, hypoxia/ischemia-injured rats pretreated with Sim were not hyperactive at weaning and showed less behavioral asymmetry. Consistently, it was found that brain damage was significantly attenuated. CONCLUSIONS: These findings indicate that prophylactic administration of statins may provide a potential neuroprotective strategy leading to an improvement in functional outcome in ischemic stroke. However, toxicity concern must be addressed before these agents can be directed to the asphyxiated fetus or newborn.

Autoradiographic localization of [3H]thiocolchicoside binding sites in the rat brain and spinal cord.

Thiocolchicoside is used in humans as a myorelaxant drug with anti-inflammatory and analgesic activity. Recently we established the experimental conditions that allowed the identification of [3H]thiocolchicoside binding sites in synaptic membranes of rat spinal cord and cerebral cortex. The pharmacological characterization of these sites indicated that GABA and several of its agonists and antagonists, as well as strychnine, were able to interact with [3H]thiocolchicoside binding in a dose-dependent manner and with different affinities. In order to gain more insight into the nature and the anatomical distribution of the binding sites labeled by [3H]thiocolchicoside, in the present study we examined the localization of these sites on parasagittal and coronal sections of the rat brain and spinal cord, respectively, using receptor autoradiography. In the spinal cord an intense signal was observed in the gray matter, with the highest density occurring in the superficial layers of the dorsal horns. Strychnine completely displaced [3H]thiocolchicoside binding, whereas GABA only partially removed the radioligand from its binding sites. In the brain, specific binding occurred in several areas and was displaced by both GABA and strychnine. The distribution of [3H]thiocolchicoside binding sites in brain sections, however, did not match that found for [3H]muscimol. Furthermore, cold thiocolchicoside was not able to completely displace [3H]muscimol binding, and showed a different efficacy in the various areas labeled by the radioligand. We conclude that thiocolchicoside may interact with a subpopulation of GABA(A) receptors having low-affinity binding sites for GABA. Furthermore, the observed sensitivity to strychnine in the spinal cord indicates an interaction also with strychnine-sensitive glycine receptors, suggesting that the pharmacological effects of thiocolchicoside may be the result of its interaction with different receptor populations.

Long-lasting behavioral alterations following a hypoxic/ischemic brain injury in neonatal rats.

The characterization of motor and cognitive dysfunctions following a neonatal ischemic injury is a prerequisite to investigate putative pharmacological interventions. To this end, in the present study, we evaluated the long-lasting behavioral alterations occurring after a hypoxic/ischemic injury obtained by the combination of monolateral carotid ligation and exposure to 8% oxygen for 3 h in 7-day-old rats. These animals show a different degree of damage in the side ipsilateral to the occluded artery. Motor coordination, tested both before and after weaning, was not affected, whereas spontaneous activity was increased at weaning but not in the adult age. When tested in an open field after apomorphine administration, most ischemic animals showed a marked turning behavior ipsilateral to the lesioned side. They also had a reduced rate of spontaneous alternation and a marked tendency to visit the arm of the T-maze ipsilateral to the lesion. Injured rats were deficient in performing water maze and T-maze acquisition tests but, when evaluated in a passive avoidance paradigm, no difference from controls was observed. These data indicate that an ischemic insult in neonatal rats causes long-lasting learning deficits and motor behavior asymmetry. These behavioral alterations may represent a useful endpoint for studying the efficacy of potential pharmacological treatments that may improve the behavioral consequences of a perinatal hypoxic/ischemic insult in humans.

Characterization of [3H]thiocolchicoside binding sites in rat spinal cord and cerebral cortex.

Thiocolchicoside, a semi-synthetic derivative of the naturally occurring compound colchicoside with a relaxant effect on skeletal muscle, has been found to displace both [3H]gamma-aminobutyric acid ([3H]GABA) and [3H]strychnine binding, suggesting an interaction with both GABA and strychnine-sensitive glycine receptors. In order to gain further insight into the interaction of thiocolchicoside with these receptors, the binding of [3H]thiocolchicoside in rat spinal cord-brainstem and cortical synaptic membranes was characterized. [3H]Thiocolchicoside binding was saturable in both tissues examined. In spinal cord-brainstem membranes, we found a K(D) of 254 +/- 47 nM and a Bmax of 2.39 +/- 0.36 pmol/mg protein, whereas in cortical membranes, a K(D) of 176 nM and a Bmax of 4.20 pmol/mg protein was observed. A similar K(D) value was found in kinetic experiments performed in spinal cord-brainstem membranes. Heterologous displacement experiments showed that GABA and strychnine displaced the binding in a dose-dependent manner, whereas glycine was ineffective. [3H]Thiocolchicoside binding was also displaced by several GABA(A) receptor agonists and antagonists, but not by baclofen, flunitrazepam, guvacine, picrotoxin or by other drugs unrelated to GABA transmission. In spinal cord-brainstem, and to a lower extent, in cortical membranes, GABA and its analogs were not able to completely displace [3H]thiocolchicoside specific binding indicating that, besides GABA(A) receptors, thiocolchicoside can bind to another unidentified site. Unlabelled thiocolchicoside, however, completely displaced [3H]muscimol binding both in cortical and in spinal cord-brainstem synaptic membranes with an IC50 in the low microM range. Neurosteroids were found to modulate the binding in cortical but not in spinal cord-brainstem synaptic membranes. We conclude that [3H]thiocolchicoside binding shows a pharmacological profile indicating an interaction with the GABA(A) receptor. The different affinities for the GABA(A) receptor agonists and antagonists and sensitivity to neurosteroids obtained in the cerebral cortex and in the spinal cord may indicate a preferential interaction of the compound with a subtype of the GABA(A) receptor. The data also indicate that [3H]thiocolchicoside binds to another site(s), whose nature remains to be elucidated.

CaMKII-dependent phosphorylation of NR2A and NR2B is decreased in animals characterized by hippocampal damage and impaired LTP.

The calcium-calmodulin-dependent protein kinase II (CaMKII) subserves activity-dependent plasticity in central neurons. To examine in vivo the implication of CaMKII activity in synaptic plasticity, we used an animal model characterized by developmentally induced targeted neuronal ablation within the cortex and the hippocampus, and showing, at presynaptic level, molecular alterations leading to facilitation of glutamate release in hippocampal synapses (methylazoxymethanol-treated rats, MAM-rats). We report here that at the postsynaptic side, the activity of CaMKII is markedly decreased in MAM-rats when compared to controls, although the concentration of the enzyme in Post Synaptic Density (PSD) is not altered. This effect is confined to PSD-associated CaMKII, as enzyme activity tested in the soluble fraction is unchanged in MAM-rats. In addition, the decreased activity is not due to inhibition by autophosphorylation in specific sites within the calmodulin-binding domain, as preincubation with purified phosphatases 1 and 2A failed to restore CaMKII activity in PSD of MAM-rats. The CaMKII-dependent phosphorylation of NR2A/B subunits of NMDA receptor is lower in MAM-rats when compared to controls (51.77 +/- 7.39% of controls level), as revealed in back-phosphorylation experiments. In addition, a treatment able to restore long-term potentiation (LTP) in hippocampal slices from MAM-rats, e.g. exposure to D-serine, is able to restore CaMKII activity to the control value.