Antiepileptic Drugs as Potential Dementia Prophylactics Following Traumatic Brain Injury.

Seizures and other forms of neurovolatility are emerging as druggable prodromal mechanisms that link traumatic brain injury (TBI) to the progression of later dementias. TBI neurotrauma has both acute and long-term impacts on health, and TBI is a leading risk factor for dementias, including chronic traumatic encephalopathy and Alzheimer's disease. Treatment of TBI already considers acute management of posttraumatic seizures and epilepsy, and impressive efforts have optimized regimens of antiepileptic drugs (AEDs) toward that goal. Here we consider that expanding these management strategies could determine which AED regimens best prevent dementia progression in TBI patients. Challenges with this prophylactic strategy include the potential consequences of prolonged AED treatment and that a large subset of patients are refractory to available AEDs. Addressing these challenges is warranted because the management of seizure activity following TBI offers a rare opportunity to prevent the onset or progression of devastating dementias.

Functional and behavioral signatures of Kv7 activator drug subtypes.

OBJECTIVE: Voltage-gated potassium channels of the KCNQ (Kv7) family are targeted by a variety of activator compounds with therapeutic potential for treatment of epilepsy. Exploration of this drug class has revealed a variety of effective compounds with diverse mechanisms. In this study, we aimed to clarify functional criteria for categorization of Kv7 activator compounds, and to compare the effects of prototypical drugs in a zebrafish larvae model. METHODS: In vitro electrophysiological approaches with recombinant ion channels were used to highlight functional properties important for classification of drug mechanisms. We also benchmarked the effects of representative antiepileptic Kv7 activator drugs using behavioral seizure assays of zebrafish larvae and in vivo Ca2+ imaging with the ratiometric Ca2+ sensor CaMPARI. RESULTS: Drug effects on channel gating kinetics, and drug sensitivity profiles to diagnostic channel mutations, were used to highlight properties for categorization of Kv7 activator drugs into voltage sensor-targeted or pore-targeted subtypes. Quantifying seizures and ratiometric Ca2+ imaging in freely swimming zebrafish larvae demonstrated that while all Kv7 activators tested lead to suppression of neuronal excitability, pore-targeted activators (like ML213 and retigabine) strongly suppress seizure behavior, whereas ICA-069673 triggers a seizure-like hypermotile behavior. SIGNIFICANCE: This study suggests criteria to categorize antiepileptic Kv7 activator drugs based on their underlying mechanism. We also establish the use of in vivo CaMPARI as a tool for screening effects of anticonvulsant drugs on neuronal excitability in zebrafish. In summary, despite a shared ability to suppress neuronal excitability, our findings illustrate how mechanistic differences between Kv7 activator subtypes influence their effects on heteromeric channels and lead to vastly different in vivo outcomes.

Medium-throughput zebrafish optogenetic platform identifies deficits in subsequent neural activity following brief early exposure to cannabidiol and Δ9-tetrahydrocannabinol.

In light of legislative changes and the widespread use of cannabis as a recreational and medicinal drug, delayed effects of cannabis upon brief exposure during embryonic development are of high interest as early pregnancies often go undetected. Here, zebrafish embryos were exposed to cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) until the end of gastrulation (1-10 h post-fertilization) and analyzed later in development (4-5 days post-fertilization). In order to measure neural activity, we implemented Calcium-Modulated Photoactivatable Ratiometric Integrator (CaMPARI) and optimized the protocol for a 96-well format complemented by locomotor analysis. Our results revealed that neural activity was decreased by CBD more than THC. At higher doses, both cannabinoids could dramatically reduce neural activity and locomotor activity. Interestingly, the decrease was more pronounced when CBD and THC were combined. At the receptor level, CBD-mediated reduction of locomotor activity was partially prevented using cannabinoid type 1 and 2 receptor inhibitors. Overall, we report that CBD toxicity occurs via two cannabinoid receptors and is synergistically enhanced by THC exposure to negatively impact neural activity late in larval development. Future studies are warranted to reveal other cannabinoids and their receptors to understand the implications of cannabis consumption on fetal development.

Seizures are a druggable mechanistic link between TBI and subsequent tauopathy.

Traumatic brain injury (TBI) is a prominent risk factor for dementias including tauopathies like chronic traumatic encephalopathy (CTE). The mechanisms that promote prion-like spreading of Tau aggregates after TBI are not fully understood, in part due to lack of tractable animal models. Here, we test the putative role of seizures in promoting the spread of tauopathy. We introduce 'tauopathy reporter' zebrafish expressing a genetically encoded fluorescent Tau biosensor that reliably reports accumulation of human Tau species when seeded via intraventricular brain injections. Subjecting zebrafish larvae to a novel TBI paradigm produced various TBI features including cell death, post-traumatic seizures, and Tau inclusions. Bath application of dynamin inhibitors or anticonvulsant drugs rescued TBI-induced tauopathy and cell death. These data suggest a role for seizure activity in the prion-like seeding and spreading of tauopathy following TBI. Further work is warranted regarding anti-convulsants that dampen post-traumatic seizures as a route to moderating subsequent tauopathy.

Traumatic brain injury can result from direct head concussions, rapid head movements, or a blast wave generated by an explosion. Traumatic brain injury often causes seizures in the short term and is a risk factor for certain dementias, including Alzheimer's disease and chronic traumatic encephalopathy in the long term. A protein called Tau undergoes a series of chemical changes in these dementias that makes it accumulate, form toxic filaments and kill neurons. The toxic abnormal Tau proteins are initially found only in certain regions of the brain, but they spread as the disease progresses. Previous studies in Alzheimer's disease and other diseases where Tau proteins are abnormal suggest that Tau can spread between neighboring neurons and this can be promoted by neuron activity. However, scientists do not know whether similar mechanisms are at work following traumatic brain injury. Given that seizures are very common following traumatic brain injury, could they be partly responsible for promoting dementia? To investigate this, researchers need animal models in which they can measure neural activity associated with traumatic brain injury and observe the spread of abnormal Tau proteins. Alyenbaawi et al. engineered zebrafish so that their Tau proteins would be fluorescent, making it possible to track the accumulation of aggregated Tau protein in the brain. Next, they invented a simple way to perform traumatic brain injury on zebrafish larvae by using a syringe to produce a pressure wave. After this procedure, many of the fish exhibited features consistent with progression towards dementia, and seizure-like behaviors. The results showed that post-traumatic seizures are linked to the spread of aggregates of abnormal Tau following traumatic brain injury. Alyenbaawi et al. also found that anticonvulsant drugs can lower the levels of abnormal Tau proteins in neurons, preventing cell death, and could potentially ameliorate dementias associated with traumatic brain injury. These drugs are already being used to prevent post-traumatic epilepsy, but more research is needed to confirm whether they reduce the risk or severity of Tau-related neurodegeneration.

Amyloid-ß precursor protein mutant zebrafish exhibit seizure susceptibility that depends on prion protein.

It has been proposed that Amyloid ß Precursor Protein (APP) might act as a rheostat controlling neuronal excitability, but mechanisms have remained untested. APP and its catabolite Aß are known to impact upon synapse function and dysfunction via their interaction with the prion protein (PrPC), suggesting a candidate pathway. Here we test if PrPC is required for this APP function in vivo, perhaps via modulating mGluR5 ion channels. We engineered zebrafish to lack homologs of PrPC and APP, allowing us to assess their purported genetic and physiological interactions in CNS development. We generated four appa null alleles as well as prp1-/-;appa-/- double mutants (engineering of prp1 mutant alleles is described elsewhere). Unexpectedly, appa-/- and compound prp1-/-;appa-/- mutants are viable and lacked overt phenotypes (except being slightly smaller than wildtype fish at some developmental stages). Zebrafish prp1-/- mutants were substantially more sensitive to appa knockdown than wildtype fish, and both zebrafish prp1 and mammalian Prnp mRNA were significantly able to partially rescue this effect. Further, appa-/- mutants exhibited increased seizures upon exposure to low doses of convulsant. The mechanism of this seizure susceptibility requires prp1 insomuch that seizures were significantly dampened to wildtype levels in prp1-/-;appa-/- mutants. Inhibiting mGluR5 channels, which may be downstream of PrPC, increased seizure intensity only in prp1-/- mutants, and this seizure mechanism required intact appa. Taken together, these results support an intriguing genetic interaction between prp1 and appa with their shared roles impacting upon neuron hyperexcitability, thus complementing and extending past works detailing their biochemical interaction(s).

Parkinsonian beta oscillations in the external globus pallidus and their relationship with subthalamic nucleus activity.

Inappropriately synchronized beta (beta) oscillations (15-30 Hz) in the subthalamic nucleus (STN) accompany movement difficulties in idiopathic Parkinson's disease (PD). The cellular and network substrates underlying these exaggerated beta oscillations are unknown but activity in the external globus pallidus (GP), which forms a candidate pacemaker network with STN, might be of particular importance. Using a clinically relevant rat model of PD, we demonstrate that oscillatory activity in GP neuronal networks becomes excessively and selectively synchronized at beta frequencies in a spatially widespread and brain state-dependent manner after lesion of dopamine neurons. Although synchronization of GP unit activity increased by almost 100-fold during beta oscillations, the mean firing rate of GP neurons decreased compared with controls. Importantly, in parkinsonian animals, two main types of GP neuron were identified according to their distinct and inversely related firing rates and patterns. Moreover, neurons of the same type tended to fire together, with small phase differences, whereas different types of neuron tended not to do so. This functional dichotomy in temporal coupling persisted across extreme brain states, suggesting that maladaptive interactions are dominated by hardwiring. Finally, the precisely timed discharges of GP and STN neurons indicated that rhythmic sequences of recurrent excitation and inhibition in the STN-GP network, and lateral inhibition between GP neurons, could actively support abnormal beta oscillations. We propose that GP neurons, by virtue of their spatiotemporal synchronization, widespread axon collaterals and feed-back/feed-forward mechanisms, are well placed to orchestrate and propagate exaggerated beta oscillations throughout the entire basal ganglia in PD.

Rhythmically active enkephalin-expressing GABAergic cells in the CA1 area of the hippocampus project to the subiculum and preferentially innervate interneurons.

Enkephalins (ENKs) are endogenous opioids that regulate synaptic excitability of GABAergic networks in the cerebral cortex. Using retrograde tracer injections in the subiculum, we identified a hippocampal population of ENK-expressing projection neurons. In situ hybridization for GAD shows that ENK-expressing cells are a small GABAergic subpopulation. Furthermore, by extracellular recording and juxtacellular labeling in vivo, we identified an ENK-expressing cell in stratum radiatum of the CA1 area by its complete axodendritic arborization and characteristic spike timing during network oscillations. The somatodendritic membrane was immunopositive for mGluR1alpha, and there was both a rich local axon in CA1 and subicular-projecting branches. The boutons showed cell-type- and layer-specific innervation, i.e., interneurons were the main targets in the alveus, both interneurons and pyramidal cell dendrites were innervated in the other layers, and interneurons were exclusive targets in the subiculum. Parvalbumin-, but not somatostatin-, calbindin-, or cholecystokinin-expressing interneurons were preferred synaptic targets. During network activity, the juxtacellularly labeled ENK-expressing cell was phase modulated throughout theta oscillations, but silenced during sharp-wave/ripple episodes. After these episodes the interneuron exhibited rebound activity of high-frequency spike bursts, presumably causing peptide release. The ENK-expressing interneurons innervating parvalbumin-positive interneurons might contribute to the organization of the sharp-wave/ripple episodes by decreased firing during and rebound activity after the ripple episodes, as well as to the coordination of activity between the CA1 and subicular areas during network oscillations.

Neuronal diversity in GABAergic long-range projections from the hippocampus.

The formation and recall of sensory, motor, and cognitive representations require coordinated fast communication among multiple cortical areas. Interareal projections are mainly mediated by glutamatergic pyramidal cell projections; only few long-range GABAergic connections have been reported. Using in vivo recording and labeling of single cells and retrograde axonal tracing, we demonstrate novel long-range GABAergic projection neurons in the rat hippocampus: (1) somatostatin- and predominantly mGluR1alpha-positive neurons in stratum oriens project to the subiculum, other cortical areas, and the medial septum; (2) neurons in stratum oriens, including somatostatin-negative ones; and (3) trilaminar cells project to the subiculum and/or other cortical areas but not the septum. These three populations strongly increase their firing during sharp wave-associated ripple oscillations, communicating this network state to the septotemporal system. Finally, a large population of somatostatin-negative GABAergic cells in stratum radiatum project to the molecular layers of the subiculum, presubiculum, retrosplenial cortex, and indusium griseum and fire rhythmically at high rates during theta oscillations but do not increase their firing during ripples. The GABAergic projection axons have a larger diameter and thicker myelin sheet than those of CA1 pyramidal cells. Therefore, rhythmic IPSCs are likely to precede the arrival of excitation in cortical areas (e.g., subiculum) that receive both glutamatergic and GABAergic projections from the CA1 area. Other areas, including the retrosplenial cortex, receive only rhythmic GABAergic CA1 input. We conclude that direct GABAergic projections from the hippocampus to other cortical areas and the septum contribute to coordinating oscillatory timing across structures.

Significance of the adrenergic system in the regulation of vasopressin secretion in rat neurohypophyseal tissue cultures.

UNLABELLED: The effects of adrenaline (A) and noradrenaline (NA) on vasopressin (VP) secretion were studied in 13-14-day cultures of isolated rat neurohypophyseal (NH) tissue. The VP contents of the supernatant media were determined by radioimmunoassay after a 1 or 2-h incubation. Significantly increased VP levels were detected in the tissue culture media following the administration of A (an alpha+beta(2)-receptor agonist), depending on the dose of A. The VP secretion elevation was totally blocked by the previous administration of phentolamine (an alpha(1)+alpha(2)-receptor antagonist) or corynanthine (an alpha(1)-receptor antagonist). Yohimbine (an alpha(2)-receptor antagonist) did not influence the VP secretion increase induced by A. After the administration of NA (a beta+alpha(1)-receptor agonist), a VP secretion elevation was again detected, but the degree of enhancement proved smaller than that of the VP secretion increase induced by A. Propranolol (a beta(1)+beta(2)-receptor antagonist) before NA administration prevented the VP secretion increase. Atenolol (a beta(1)-receptor antagonist) did not block the VP secretion elevation induced by NA. Corynanthine (an alpha(1)-receptor antagonist) treatment before NA administration reduced the NA-induced VP enhancement, because NA has an alpha(1)-receptor agonist character in addition to its main character (a beta-receptor agonist). Surprisingly, the administration of pindolol (a beta(1)+beta(2)-receptor antagonist) enhanced VP secretion. This contradictory effect can be explained in that pindolol not only acts as a blocker, but also exerts "intrinsic sympathomimetic action" and a strong adrenergic agonist effect. Pindolol before NA administration significantly increased the NA-induced VP elevation. CONCLUSIONS: Mainly the alpha(1)- and beta(2)-adrenergic receptors are involved in the A- or NA-induced increase of VP secretion in isolated NH tissue cultures. The results indicate that VP release is influenced directly by the adrenergic system, and the adrenergic control of VP secretion from the NH tissue in rats can occur at the level of the posterior pituitary.

Expected poor ovarian response in predicting cumulative pregnancy rates: a powerful tool.

Poor ovarian response in IVF cycles is associated with poor pregnancy rates. Expected poor responders may represent the worst prognostic group. Data were used from 222 patients starting the first of three IVF treatment cycles. The predictability of ongoing pregnancy after three cycles was analysed using survival analysis and hazard rate ratios. If first cycle poor responders were also predicted to have a poor response, they were classified as expected poor responders. The predicted pregnancy rate in cycles 2 and 3 for women with an observed poor response in the first cycle was approximately 24% for women aged 30 years and approximately 14% for women aged 40 years. For women with an expected poor response these rates were 12% and 6%, respectively. In contrast, women aged 40 years with an unexpected poor response still had a predicted cumulative pregnancy rate of 24%. Age as a sole predictor of cumulative pregnancy does not help to identify poor prognosis cases. Cumulative pregnancy rates in subsequent cycles for patients with an observed poor response in the first cycle may be a reason to refrain from further treatment. However, if such poor response has been expected, further treatment may be avoided because of an unfavourable prognosis for pregnancy.

Inhibitory effect of vasopressin receptor antagonist OPC-31260 on experimental brain oedema induced by global cerebral ischaemia.

The effects of the non-peptide vasopressin V(2) receptor antagonist 5-dimethylamino-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC-31260) on the cerebral oedema induced by general cerebral hypoxia were studied in rats. The general cerebral hypoxia was produced by bilateral common carotid ligation in Sprague-Dawley rats of the CFY strain. By 6 h after the ligation, half of the rats had died, but the survival rate was significantly higher following OPC-31260 administration. Electron microscopic examinations revealed typical ischaemic changes after the carotid ligation. The carotid ligation increased the brain contents of water and Na(+) and enhanced the plasma vasopressin level. The increased brain water and Na(+) accumulation was prevented by OPC-31260 administration, but the plasma vasopressin level was further enhanced by OPC-31260. These results demonstrate the important role of vasopressin in the development of the disturbances in brain water and electrolyte balance in response to general cerebral hypoxia. The carotid ligation-induced cerebral oedema was significantly reduced following oral OPC-31260 administration. The protective mechanism exerted by OPC-31260 stems from its influence on the renal vasopressin V(2) receptors. These observations might suggest an effective approach to the treatment of global hypoxia-induced cerebral oedema in humans.

Spike timing of dendrite-targeting bistratified cells during hippocampal network oscillations in vivo.

Behavior-contingent network oscillations bring about transient, functionally coherent neuronal assemblies in the cerebral cortex, including the hippocampus. Inhibitory input on and close to the soma is believed to phase intrinsic oscillations and output of pyramidal cells, but the function of GABA release to pyramidal cell dendrites remains unknown. We recorded the oscillation-locked spike timing of identified bistratified interneurons in rats. These cells mainly innervated small dendritic shafts of pyramidal cells co-aligned with the glutamatergic Schaffer collateral/commissural input. During theta oscillations, bistratified cells fired at a phase when, on average, pyramidal cell dendrites are most hyperpolarized. Interneurons targeting the perisomatic domain discharge at an earlier phase. During sharp wave-associated ripples, bistratified cells fired with high frequency and in-phase with basket cells, on average 1-2 ms after the discharges in pyramidal cell somata and dendrites. Our results indicate that bistratified cells rhythmically modulate glutamatergic input to the dendrites of pyramidal cells to actively promote the precise input/output transformation during network oscillations.

Rigorous biogenetic network for a group of indole alkaloids derived from strictosidine.

Strictosidine, the precursor of more than 2,500 indole alkaloids, was isolated from four species of three plant families. By searching the Dictionary of Natural Products on DVD it was found that about 150 indole alkaloids were obtained from the same species (coalkaloids), which is a direct proof of their common origin. On the base of their three-dimensional structure, taxonomic properties and standard reaction mechanisms an extended network was established which involved the four fundamental skeletons, the three types of carbon framework in the secologanin subunit and all major groups of indole alkaloids derived from secologanin and tryptamine (except a few minor groups, in which only less then 10 alkaloids were known). The system was extended to the heterodimer indole alkaloids and the quinoindole alkaloids as well.

Complementary roles of cholecystokinin- and parvalbumin-expressing GABAergic neurons in hippocampal network oscillations.

In the hippocampal CA1 area, a relatively homogenous population of pyramidal cells is accompanied by a diversity of GABAergic interneurons. Previously, we found that parvalbumin-expressing basket, axo-axonic, bistratified, and oriens-lacunosum moleculare cells, innervating different domains of pyramidal cells, have distinct firing patterns during network oscillations in vivo. A second family of interneurons, expressing cholecystokinin but not parvalbumin, is known to target the same domains of pyramidal cells as do the parvalbumin cells. To test the temporal activity of these independent and parallel GABAergic inputs, we recorded the precise spike timing of identified cholecystokinin interneurons during hippocampal network oscillations in anesthetized rats and determined their molecular expression profiles and synaptic targets. The cells were cannabinoid receptor type 1 immunopositive. Contrary to the stereotyped firing of parvalbumin interneurons, cholecystokinin-expressing basket and dendrite-innervating cells discharge, on average, with 1.7 +/- 2.0 Hz during high-frequency ripple oscillations in an episode-dependent manner. During theta oscillations, cholecystokinin-expressing interneurons fire with 8.8 +/- 3.3 Hz at a characteristic time on the ascending phase of theta waves (155 +/- 81 degrees), when place cells start firing in freely moving animals. The firing patterns of some interneurons recorded in drug-free behaving rats were similar to cholecystokinin cells in anesthetized animals. Our results demonstrate that cholecystokinin- and parvalbumin-expressing interneurons make different contributions to network oscillations and play distinct roles in different brain states. We suggest that the specific spike timing of cholecystokinin interneurons and their sensitivity to endocannabinoids might contribute to differentiate subgroups of pyramidal cells forming neuronal assemblies, whereas parvalbumin interneurons contribute to synchronizing the entire network.

Histamine-induced enhancement of vasopressin and oxytocin secretion in rat neurohypophyseal tissue cultures.

The effects of histamine (HA) on vasopressin (VP) and oxytocin (OT) secretion were studied in 13-14-day cultures of isolated rat neurohypophyseal (NH) tissue. The VP and OT contents of the supernatant were determined by radioimmunoassay (RIA) after a 1 or 2-h incubation. Significantly increased levels of VP and OT production were detected in the tissue culture media following HA administration, depending on the HA dose. The elevation of NH hormone secretion could be partially blocked by previous administration of the HA antagonist mepyramine (MEP, an H1 receptor antagonist) or cimetidine (CIM, an H2 receptor antagonist). Thioperamide (TPE, an H3-H4 receptor antagonist) did not influence the VP or OT secretion increase induced by HA. The application of MEP, CIM or TPE after HA administration proved ineffective. The H1 and H2 receptors are mainly involved in the HA-induced increase of both VP and OT secretion in isolated NH tissue cultures. The results indicate that NH hormone release is influenced directly by the histaminergic system, and the histaminergic control of VP and OT secretion from the NH tissue in rats can occur at the level of the posterior pituitary.

Five different adenomas derived from the rat adenohypophysis: immunocytochemical and ultrastructural study.

With the use of electron microscopic morphology and immunochemistry, 5 tumors were studied: a spontaneous prolactin-producing adenoma (LEP rats); an estrogen-induced intrasellar tumor (R-Amsterdam rats); and 3 transplanted tumors, MtT.W10 and MtT.W5 (WF rats) and MtT.F4 (F344 rats). All tumors were derived from rat adenohypophysis and are known to secrete prolactin, growth hormone, or adrenocorticotropic hormone. The spontaneous tumor consisted of a uniform population of cells containing only immunoreactive prolactin. In the estrogen-induced tumor, prolactin and growth hormone were localized in separate cell types with the use of the immunoperoxidase technique. In the MtT.W10 tumor, both immunoreactive prolactin and growth hormone were observed in the same cell and in separate cell types. In the MtT.F4 and MtT.W5 tumors, one cell type was identified that was characterized by lack of morphologic differentiation, reduced secretory granule number, and inconclusive immunopositivity.

Serotonin-induced enhancement of vasopressin and oxytocin secretion in rat neurohypophyseal tissue culture.

The effects of serotonin (5-hydroxytryptamine; 5-HT) on vasopressin (VP) and oxytocin (OT) secretion were studied in 13-14-day cultures of isolated rat neurohypophyseal (NH) tissue. The VP and OT contents of the supernatant were determined by radioimmunoassay after a 1 or 2 h incubation. Significantly increased levels of VP and OT production were detected in the tissue culture media following 5-HT administration, depending on the 5-HT dose. The elevation of NH hormone secretion could be partially blocked by previous administration of the 5-HT antagonist ketanserin or metergoline. WAY-100635 did not influence the increased VP secretion induced by 5-HT, but the elevated OT production was prevented by WAY-100635 before 5-HT administration. The application of WAY-100635, ketanserin or metergoline, after 5-HT administration proved ineffective. The results indicate that NH hormone release is influenced directly by the serotonergic system. The serotonergic control of VP and OT secretion from the NH tissue in rats can occur at the level of the posterior pituitary.

Antral follicle count in the prediction of poor ovarian response and pregnancy after in vitro fertilization: a meta-analysis and comparison with basal follicle-stimulating hormone level.

OBJECTIVE: To assess the predictive performance of the antral follicle count (AFC) as a test for ovarian reserve in IVF patients and to compare this performance with that of basal FSH level. DESIGN: Meta-analysis. SETTING: Tertiary fertility center. PATIENT(S): Patients undergoing IVF. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Poor ovarian response, nonpregnancy. RESULT(S): We identified 11 studies on AFC and an updated total of 32 studies on basal FSH from the literature on the basis of preset criteria. The estimated summary receiver operating characteristic (ROC) curves showed AFC to perform well in the prediction of poor ovarian response. Also, prediction of poor ovarian response seemed to be more accurate with AFC compared with basal FSH. The estimated summary ROC curves for the prediction of nonpregnancy indicated a poor performance for both AFC and basal FSH. CONCLUSION(S): Transvaginal ultrasonography is an easy-to-perform and noninvasive method that provides essential predictive information on ovarian responsiveness. The predictive performance of AFC toward poor response is significantly better than that of basal FSH. Therefore, AFC might be considered the test of first choice in the assessment of ovarian reserve prior to IVF.

Changes of the nutrient loads of the Danube since the late eighties: An analysis based on long term changes along the whole Danube River and its main tributaries.

The Danube nutrient loads are affected by human impacts mainly from agriculture and wastewater discharges. Knowledge about the Danube nutrient loads and the changes of these loads over time is essential for understanding the changes within the ecosystem of the Black Sea, induced by these loads. The paper shows the long term changes of the nutrient load along the Danube estimated by measurements from different countries and institutions. The results show large differences between Dissolved Inorganic Nitrogen (DIN) and Total Phosphorus (TP). For TP, the Danube River loads show a strong decrease since 1988-1992, especially in the Middle and Lower basin. This change is probably partly connected to the dramatic economic changes in the Middle and Eastern European countries following the collapse of the communist system. The DIN load does not show a decreasing trend in the last decade. The data indicate that there may be a decreasing trend in the anthropogenic emissions, but that such a trend is counteracted by a significantly increasing trend of the Danube discharge in the last decade. The accuracy of the available data is analysed in the paper as well.

Endogenous nitric oxide in the maintenance of rat microvascular integrity against widespread plasma leakage following abdominal laparotomy.

1. The role of nitric oxide (NO) in the maintenance of microvascular integrity during minor surgical manipulation has been evaluated in the rat. 2. The NO synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME, 5 mg kg(-1), s.c.) and N(G)-monomethyl-L-arginine (L-NMMA, 50 mg kg(-1), s.c.) had no effect on microvascular leakage of radiolabelled albumin over 1 h in the stomach, duodenum, jejunum, colon, lung and kidney in the un-operated conscious or pentobarbitone-anaesthetized rat. 3. In contrast, in anaesthetized rats with a midline abdominal laparotomy (5 cm), L-NAME (1-5 mg kg(-1), s.c.) or L-NMMA (12.5-50 mg kg(-1), s.c.) dose-dependently increased gastrointestinal, renal and pulmonary vascular leakage, effects reversed by L-arginine pretreatment (300 mg kg(-1), s.c., 15 min). These actions were not observed in anaesthetized rats that had only received a midline abdominal skin incision (5 cm). 4. Pretreatment with a rabbit anti-rat neutrophil serum (0.4 ml kg(-1), i.p.), 4 h before laparotomy, abolished the plasma leakage induced by L-NAME in all the organs investigated. 5. These results indicate that the following abdominal laparotomy, inhibition of constitutive NO synthase provokes vascular leakage in the general microcirculation, by a process that may involve neutrophils. Such effects could thus confound studies on the microvascular actions of NO synthase inhibitors using acute surgically prepared in vivo models. The findings thus suggest that constitutively-formed NO has a crucial role in the maintenance of acute microvascular integrity following abdominal surgical intervention.