Recombinant Erythropoietin and Analogues

Erythropoietin (EPO) increases the number of circulating erythrocytes and thus muscle oxygenation. The availability of the recombinant protein (rEPO) has increased the risk of its illegal use in sports, its detection being a difficult challenge. Five different hematopoietic parameters were initially chosen as indirect markers of rEPO abuse: concentration of serum EPO, concentration of serum-soluble transferrin receptors (sTFr), hematocrit, percentage of reticulocytes, and percentage of macrocytes. New models considering only hemoglobin, serum EPO concentration, and percentage of reticulocytes are simpler and seem to be more sensitive when low doses of rEPO are used. A more direct method of urine analysis (isoelectrofocusing, double blotting, and chemiluminescent detection) based on the charge differences between rEPO and endogenous EPO, related to their carbohydrate composition, provides proof of rEPO use. Furthermore, this approach permits the detection of darbepoetin, a direct analogue of EPO also known as NESP ("new erythropoiesis stimulating protein"). Recently a protein conjugate, "synthetic erythropoiesis protein" (SEP), containing precision-length, monodisperse, negatively charged polymers instead of oligosaccharides has been synthesized. Finally, EPO-mimetics are molecules capable of acting as EPO in dimerizing the EPO receptor. Two kinds of EPO-mimetics have been described: peptides and nonpeptides. The enhancement of oxygen availability to muscles by rEPO, analogues, and mimetics constitutes one of the main challenges to doping control. Major steps have already been developed for detection ofrEPO and some analogues. In the near future, the transfection to an athlete's body of genes that code for erythropoietin might be an emerging doping issue, and sports authorities have incorporated "gene doping" among the prohibited practices.

Encephalopathy secondary to imipenem therapy

We describe the case of an 84-year-old woman who developed a confusional state and suffered from a generalized tonic-clonic seizure while she was treated with imipenem, a beta-lactam antibiotic. Focal and generalized epileptiform discharges and a photoparoxysmal response were prominent with transient changes on the EEG.

Mucus physiopathology, update and new therapeutic tendencies

The knowledge of mucous secretions has advanced considerably with respect to their altered physiological properties in various ear, nose and throat disorders. We review the physicochemical properties of normal mucus and abnormal mucus present in the airways during sinusitis, otitis media with effusion, etc. We have adapted the mucoactive drugs classification to the up-to-date european situation, presenting a bibliographic review. We have attempted to reconcile the agreed findings in the literature with the most recent advances in research that have resulted in new therapeutic strategies for the treatment of pathological hypersecretion in the airways.

A catalogue of molecular, physiological and symbiotic properties of soybean-nodulating rhizobial strains from different soybean cropping areas of China

We have analysed 198 fast-growing soybean-nodulating rhizobial strains from four different regions of China for the following characteristics: generation time; number of plasmids; lipopolysaccharide (LPS), nodulation factors (LCOs) and PCR profiles; acidification of growth medium; capacity to grow at acid, neutral, and alkaline pH; growth on LC medium; growth at 28 and 37 degrees C; melanin production capacity; Congo red absorption and symbiotic characteristics. These unbiased analyses of a total subset of strains isolated from specific soybean-cropping areas (an approach which could be called "strainomics") can be used to answer various biological questions. We illustrate this by a comparison of the molecular characteristics of five strains with interesting symbiotic properties. From this comparison we conclude, for instance, that differences in the efficiency of nitrogen fixation or competitiveness for nodulation of these strains are not apparently related to differences in Nod factor structure.

Organophosphorus pesticide residues in Mexican commercial pasteurized milk

A study was conducted to measure residues of 13 organophosphorus (OP) pesticides, widely used as dairy cattle ectoparasiticides or in crops used for animal feed, in homogenized and pasteurized Mexican milk samples. Four different milk brands with high distribution were collected biweekly during a 12 month period (n = 96) in supermarkets. OP pesticide residues were measured by gas chromatography with a flame photometric detector. Approximately 39.6% of the samples contained detectable levels of OP pesticide residues. Eight samples contained residues exceeding established maximum residue limits (MRL), and the OP pesticides present in these samples were dichlorvos (five samples), phorate, chlorpyrifos, and chlorfenvinphos (one sample, respectively). Average residues of 13 OP pesticides measured were below established MRLs ranging between 0.0051 and 0.0203 ppm.

High-performance thin-layer chromatography-bioautography for multiple antibiotic residues in cow's milk

An analytical method to identify and quantify multiple antibiotic residues (chloramphenicol, ampicillin, benzylpenicillin, dicloxacillin and erythromycin) in cow's milk by high-performance thin-layer chromatography (HPTLC) combined with bioautography was developed. The test microorganism used for bioautography was Bacillus subtilis ATCC 6633. Antibiotic residues were extracted with acetonitrile, fat eliminated with petroleum ether and residues isolated with dichloromethane The sensitivity of the method guarantees the detection of the above-mentioned antibiotics at levels below maximum residue limits (MRL) allowed for milk. Percentage recoveries ranged between 90 and 100%, with coefficients of variation between 7.2 and 21.3%. Some advantages of this methodology over thin-layer chromatography (TLC)/bioautography are also discussed.

[Interaction between sildenafil and calcineurin inhibitors in renal transplant recipients with erectile dysfunction]

AIM

Hepatic metabolism of sildenafil uses the same metabolic pathway as the calcineurin inhibitors (cyclosporine/tacrolimus), through the CYP3A4 isoenzyme. The aim of this pilot study was to evaluate the potential interaction between sildenafil therapy and circulating levels of cyclosporine and tacrolimus in a group of steady-state renal transplant recipients with erectile dysfunction.

MATERIAL AND METHODS

A prospective pilot study of sildenafil interactions was carried out in 9 stable male renal transplant recipients with severe erectile dysfunction (mean age 50 +/- 8 years, range 38-64). All patients were receiving therapy with calcineurin inhibitors (5 with cyclosporine and 4 with tacrolimus). Erectile dysfunction was evaluated by clinical history, physical examination, International Index of Erectile Function (IIEF) questionnaire and the nocturnal penile tumescence test (RigiScan). Each patient received a first dose of 50 mg of sildenafil, one hour before sexual activity and a second dose at 72 hours of 50 or 100 mg according to the clinical response to the first dose. We evaluated the efficacy and safety of sildenafil and the evolution of cyclosporine-tacrolimus levels. Cyclosporine and tacrolimus trough whole blood concentrations were determined in basal conditions (before starting sildenafil) and on days 1, 4 and 7 after sildenafil therapy.

RESULTS

Eighty-nine percent of patients (n = 8) required a complete 100 mg dose of sildenafil. There was a positive clinical response in two-thirds of cases (6 patients). In 5 patients (55%) sildenafil administration produced a complete response, in one patient the response was incomplete, and in the remaining 3 cases (33%) no clinical response was observed. Associated side effects included self-limited tachycardia in one patient and mild visual disturbances in another. Cyclosporine and tacrolimus levels remained stable in all patients. There were no significant differences in circulating levels of cyclosporine (basal 120 +/- 47; day 1: 116 +/- 55; day 4: 123 +/- 56 and day 7: 121 +/- 56 ng/ml p = NS) or tacrolimus (basal 11.6 +/- 1.3; day 1: 11.9 +/- 1.3; day 4: 11.1 +/- 1.0 and day 7: 11.8 +/- 0.9 ng/ml p = NS) over the study period.

CONCLUSIONS

Sildenafil therapy is safe and effective for the treatment of erectile dysfunction in renal transplant recipients. Recommended therapeutic doses of sildenafil did not modify cyclosporine and tacrolimus trough blood levels.

[Lymphoma of the nasal cavity, clinical and anatomo-pathologic considerations]

Six cases of high-grade lymphoma affecting the nasal cavity are presented. Their main symptoms were nasal obstruction, epistaxis and rhinorrea. Clinical exploration showed an ulcerated lesion in four patients (all of them T/NK cell lymphomas) and an exofitic tumour in the other two (B cell lymphomas). Pathology was diagnostic for high grade lymphoma in all the six cases, immunohistochemical studies revealed that the atypical cells were T/NK in 4 cases and B in the other two cases. Genotypic analysis was done looking for rearrangement of the genes for Ig H or T-cell receptors. In situ hybridisation was done to detect Epstein-Barr virus RNA. Malignant lymphomas arising in the nasal cavity are unusual, its major prognostic factor is the clinical stage at presentation. To perform an early diagnosis this neoplasia must be suspected in the presence of an exofitic tumour (B cell lymphoma) or necrotic and ulcerated lesion (T/NK cell lymphoma).

Differential involvement of cortical muscarinic and NMDA receptors in short- and long-term taste aversion memory

In conditioned taste aversion, an animal avoids a taste previously associated with toxic effects, and this aversive memory formation requires an intact insular cortex. In this paper, we investigated the possible differential involvement of cholinergic and glutamatergic receptors in the insular cortex in short-term memory (STM) and long-term memory (LTM) of taste aversion in rats. Taste aversion was induced by intraperitoneal administration of lithium chloride (a malaise-inducing drug) 15 min after experience with an unfamiliar taste. In order to test STM and LTM of taste aversion, taste stimulus was again presented 4 h and 72 h after lithium injection, respectively. During the acquisition, microinjection of the muscarinic antagonist, scopolamine, in the insular cortex before, but not after, the presentation of the new taste, abolished STM as well as LTM. Blockade of the NMDA receptor, in the insular cortex, by AP5 before, but not after, the presentation of the taste stimulus, impaired LTM but left STM intact. Moreover, when injected 1 h after malaise induction (i.e., during taste-illness association), AP5 disrupted both STM and LTM. These results suggest that activation of muscarinic receptors in the insular cortex is involved in the acquisition of taste memory, whereas NMDA receptors participate in taste memory consolidation. These data demonstrate that different neurochemical mechanisms subserve different memory phases. NMDA receptors are also probably involved in processing the visceral input, thus allowing subsequent taste-illness association. This indicates that in the same cortical area the same neurotransmitter system can be involved in distinct processes: taste memory consolidation vs. taste-illness association.

The expression of GABA in mossy fiber synaptosomes coincides with the seizure-induced expression of GABAergic transmission in the mossy fiber synapse

Although the granule cells of the dentate gyrus are glutamatergic, they contain the machinery for the synthesis and vesiculation of GABA. Furthermore, glutamic acid decarboxylase and the vesicular GABA transporter mRNA are expressed in the granule cells and mossy fibers in an activity-dependent manner, suggesting that these cells release GABA in addition to glutamate. Supporting this hypothesis, we found that seizures induce simultaneous glutamatergic and GABAergic transmission in the mossy fiber projection. To further explore this expression of inhibition, we looked for the presence and expression of endogenous GABA in a synaptosomal preparation enriched with mossy fiber nerve endings of kindled rats. We also studied the capacity of this preparation to capture and release [(3)H]GABA under control conditions and after kindling epilepsy. In accordance with our hypothesis we show that the mossy fiber synaptosomal preparation of the kindled rats has a significantly higher content of endogenous GABA than controls. We also found that the protein content in the mossy fiber synaptosomal preparation of kindled rats was significantly augmented, which is consistent with mossy fiber sprouting. Due to this, the total [(3)H]GABA incorporated in the synaptosomal preparation was also augmented. However, [(3)H]GABA uptake (expressed in % radioactivity/mg protein) and its evoked release were similar in both groups. With the present results, we provide further support for the hypothesis of the emergence of GABAergic transmission in the mossy fiber synapse that can constitute a protective mechanism in response to seizures.

Differential effects of bicuculline and muscimol microinjections into the nucleus basalis magnocellularis in taste and place aversive memory formation

The role of the nucleus basalis magnocellularis (NBM) in learning and memory has been demonstrated in different learning paradigms such as conditioned taste aversion (CTA) and inhibitory avoidance (IA). This participation has been related to the cholinergic system, but recent studies have reported the potential role of other neurotransmitters such as GABA. The effects of acute intracerebral administration of the GABAergic antagonist bicuculline (0.05 microg) and the GABAergic agonist muscimol (0.05 microg) into the NBM of male Wistar rats were assessed in CTA and IA learning. In both learning tasks, the drug administration was performed before the acquisition. Taste aversion learning was not affected by the infusion of any of the drugs administered. IA acquisition was not affected by the administration of bicuculline or muscimol, requiring similar number of trials to reach the learning criterion. However, when the rats were tested 24 h later, those injected with bicuculline or muscimol showed an impairment of the IA learning. The present results support a role of the GABAergic system in the consolidation process of IA learning.

Immunoglobulins anti-Anisakis simplex in patients with gastrointestinal diseases

The nematode Anisakis simplex causes anisakidiasis, a disease that often mimics other gastrointestinal diseases. Patients with digestive haemorrhaging, Crohn's disease, digestive cancer and appendicitis were analysed for antibodies to A. simplex. Antibody detection was carried out by enzyme-linked immunosorbent assay (ELISA) and immunoblotting using crude extract (CE) antigen and excretory-secretory (ES) products. Total immunoglobulin (Igs), IgG, IgM, IgA and IgE were studied. The highest percentage was obtained when Igs were tested against CE antigen. A higher percentage of positivity was observed with the appendicitis group. The Crohn's disease group showed the highest levels of IgG against the ES antigen. Using immunoblotting, 24% and 48% of sera from patients with symptoms of Crohn's disease and digestive haemorrhaging, respectively, showed a positive immunorecognition pattern of CE antigen. The prevalence of detectable antibodies against A. simplex is higher in patients with digestive disorders than in the healthy population. A linear correlation was observed between prothrombin activity and Igs-CE, IgA-CE and IgA-ES but not between IgE-CE and the other immunoglobulin levels. Specific IgA is associated with a higher activity index of Crohn's disease. Specific antibodies were observed against A. simplex in patients with appendicitis and gastrointestinal cancer, indicating a higher rate of positivity for IgA.

Activity-dependent expression of GAD67 in the granule cells of the rat hippocampus

In the normal granule cells of the dentate gyrus glutamate, GABA and glutamic acid decarboxylase (GAD67) coexist. After kindled seizures, this enzyme is transiently overexpressed and simultaneous glutamatergic and GABAergic transmission in the mossy fiber projection occurs. Since this dual transmission is also seen after acutely-induced seizures, we decided to study the relationship between the expression of GAD67 and the induction of simultaneous glutamatergic and GABAergic transmission by kindled or acutely induced seizures. We also explored whether kindling of the dentate gyrus in vitro, that does not induce epileptiform activity, could induce the expression of GAD67. We confirm that kindling epilepsy induces the expression of GAD67 in the dentate gyrus. Despite the emergence of GABAergic transmission in the mossy fiber projection after a single seizure, GAD67 expression in the dentate gyrus appeared similar to controls, however, in the mossy fibers an enhanced immunostaining was evident. Interestingly, kindling the dentate gyrus in vitro induces a marked GAD67 staining in the granule cells. Our results show that after the activity-dependent emergence of simultaneous glutamatergic and GABAergic transmission from the mossy fibers, GAD67 is expressed in the mossy fibers and, upon long-lasting enduring stimulation periods, also in the dentate gyrus. Thus, this phenomenon does not depend on the presence of epileptic activity, but rather, on increased excitatory input onto the dentate gyrus. This can represent a protective mechanism that can sustain GABA synthesis in an activity-dependent manner.

Effect of pH and soybean cultivars on the quantitative analyses of soybean rhizobia populations

Quantitative analyses of fast- and slow-growing soybean rhizobia populations in soils of four different provinces of China (Hubei, Shan Dong, Henan, and Xinjiang) have been carried out using the most probable number technique (MPN). All soils contained fast- (FSR) and slow-growing (SSR) soybean rhizobia. Asiatic and American soybean cultivars grown at acid, neutral and alkaline pH were used as trapping hosts for FSR and SSR strains. The estimated total indigenous soybean-rhizobia populations of the Xinjiang and Shan Dong soil samples greatly varied with the different soybean cultivars used. The soybean cultivar and the pH at which plants were grown also showed clear effects on the FSR/SSR rations isolated from nodules. Results of competition experiments between FSR and SSR strains supported the importance of the soybean cultivar and the pH on the outcome of competition for nodulation between FSR and SSR strains. In general, nodule occupancy by FSRs significantly increased at alkaline pH. Bacterial isolates from soybean cultivar Jing Dou 19 inoculated with Xinjiang soil nodulate cultivars Heinong 33 and Williams very poorly. Plasmid and lipopolysaccharide (LPS) profiles and PCR-RAPD analyses showed that cultivar Jing Dou 19 had trapped a diversity of FSR strains. Most of the isolates from soybean cultivar Heinong 33 inoculated with Xinjiang soil were able to nodulate Heinong 33 and Williams showed very similar, or identical, plasmid, LPS and PCR-RAPD profiles. All the strains isolated from Xinjiang province, regardless of the soybean cultivar used for trapping, showed similar nodulation factor (LCO) profiles as judged by thin layer chromatographic analyses. These results indicate that the existence of soybean rhizobia sub-populations showing marked cultivar specificity, can affect the estimation of total soybean rhizobia populations indigenous to the soil, and can also affect the diversity of soybean rhizobial strains isolated from soybean nodules.

Arterial wall neovascularization induced by glycerol

An intense and significant neovascularization, with numerous capillaries growing into the media layer of the rat femoral artery, was demonstrated when glycerol was administered into the interstitium between the femoral vein and the femoral artery. The maximum microvascularization was observed at days 7 and 9 after glycerol administration. Afterwards, involution of the majority of the newly-formed microvessels in the arterial wall occurred. Other substances containing glycerol in their molecules, such as triacetyl-glycerol and tributyril-glycerol, failed to produce significant neovascularization in the media layer of the femoral artery. Neovascularization of the arterial wall was preceded by a considerable decrease in the number of the smooth muscle cells, which experienced apoptosis and necrobiosis, disappearing in extense areas of the arterial segment affected by glycerol. Coinciding with neovascularization and microvascular involution, repopulation of the media layer by smooth muscle cells was observed.

Vesicular GABA transporter mRNA expression in the dentate gyrus and in mossy fiber synaptosomes

In the normal granule cells of the dentate gyrus, glutamate and both gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD) coexist. GAD expression is increased after seizures, and simultaneous glutamatergic and GABAergic neurotransmission from the mossy fibers to CA3 appears, supporting the hypothesis that GABA can be released from the mossy fibers. To sustain GABAergic neurotransmission, the amino acid must be transported into synaptic vesicles. To address this, using RT-PCR we looked for the presence and regulation of expression of the vesicular GABA transporter (VGAT) mRNA in the dentate gyrus and in mossy fiber synaptosomes of control and kindled rats. We found trace amounts of VGAT mRNA in the dentate gyrus and mossy fiber synaptosomes of control rats. In the dentate gyrus of kindled rats with several seizures and of control rats subject to one acute seizure, no changes were apparent either 1 or 24 h after the seizures. However, repetitive synaptic or antidromic activation of the granule cells in slices of control rats in vitro induces an activity-dependent enhancement of VGAT mRNA expression in the dentate. Surprisingly, in the mossy fiber synaptosomes of seizing rats, the levels of VGAT mRNA were significantly higher than in controls. These data show that the granule cells and their mossy fibers, besides containing machinery for the synthesis of GABA, also contain the elements that support its vesiculation. This further supports the notion that local synaptic molecular changes enable mossy fibers to release GABA in response to enhanced excitability.

Acute neck infections: prospective comparison between CT and MRI in 47 patients

PURPOSE

The purpose of this work was to assess the advantages and disadvantages of MRI versus CT in the initial evaluation of acute infections involving the neck.

METHOD

We prospectively evaluated 47 patients with neck infections. All patients underwent CT and MRI with contrast of the area of interest using similar slice thickness. Final diagnosis was achieved by percutaneous aspiration, surgical exploration and drainage, or follow-up after successful antibiotic therapy in all patients. Two radiologists reviewed all imaging studies with special attention to lesion conspicuity, location, extension, bone involvement, source of infection (odontogenic versus nonodontogenic), and presence of gas and/or calcium in the lesions. A 3 point scale was used to grade these parameters, and statistical comparison was done using paired t test.

RESULTS

As used in our population, MRI was superior to CT in regard to lesion conspicuity, number of anatomic spaces involved, extension, and source. Additionally, although not statistically significantly, MRI detected a greater number of abscess collections. CT was superior to MRI in the detection of intralesional gas and calcium and showed fewer motion artifacts. These advantages of CT were, however, not significantly better than those of MRI.

CONCLUSION

As used in our study, MRI was considered superior to CT in the initial evaluation of neck infections. Our findings suggest that MRI may be used as the first and perhaps the only modality to initially evaluate patients with neck infections when clinically feasible.

Kindling induces transient fast inhibition in the dentate gyrus--CA3 projection

The granule cells of the dentate gyrus (DG) send a strong glutamatergic projection, the mossy fibre tract, toward the hippocampal CA3 field, where it excites pyramidal cells and neighbouring inhibitory interneurons. Despite their excitatory nature, granule cells contain small amounts of GAD (glutamate decarboxylase), the main synthetic enzyme for the inhibitory transmitter GABA. Chronic temporal lobe epilepsy results in transient upregulation of GAD and GABA in granule cells, giving rise to the speculation that following overexcitation, mossy fibres exert an inhibitory effect by release of GABA. We therefore stimulated the DG and recorded synaptic potentials from CA3 pyramidal cells in brain slices from kindled and control rats. In both preparations, DG stimulation caused excitatory postsynaptic potential (EPSP)/inhibitory postsynaptic potential (IPSP) sequences. These potentials could be completely blocked by glutamate receptor antagonists in control rats, while in the kindled rats, a bicuculline-sensitive fast IPSP remained, with an onset latency similar to that of the control EPSP. Interestingly, this IPSP disappeared 1 month after the last seizure. When synaptic responses were evoked by high-frequency stimulation, EPSPs in normal rats readily summate to evoke action potentials. In slices from kindled rats, a summation of IPSPs overrides that of the EPSPs and reduces the probability of evoking action potentials. Our data show for the first time that kindling induces functionally relevant activity-dependent expression of fast inhibition onto pyramidal cells, coming from the DG, that can limit CA3 excitation in a frequency-dependent manner.

[Hormonal alterations on young morbid obese women]

BACKGROUND

Human obesity is a widespread disease with considerable variability as to its severity, metabolic and endocrine manifestations and etiology. In the present study we have determined whether the alterations of uncomplicated severe obesity in adult young women affect with different intensity the circulating levels of hormones that have been postulated to intervene in the development and maintenance of obesity.

SUBJECTS AND METHOD

Age-matched 20 morbidly obese (BMI 52.6 [8.3 SD] kg/m2) and 10 normal-weight control women (BMI 19.9 [2.1 SD] kg/m2)were studied and determined the basal circulating levels of hormones and proteins related with the control of body weight.

RESULTS

Obese women showed higher concentrations of insulin and leptin, and lower of cortisol and cortisol-binding globulin (CBG). No significant differences were appreciated for free thyroxine, TSH, free and acylestrone and dehydroepiandrosterone-sulphate.

CONCLUSIONS

The results suggest that morbid obesity implies the alteration of the main hormonal systems controlling the availability of energy and the response to external challenges, with the noteworthy exception of the thyroid. There were clear alterations of insulin and leptin,but cortisol changes could be more related to factors other than obesity. The lower than expected levels of acylestrone point to a possible deficit of this ponderostat signal in obese women. The relatively young age of the women in the study may account for the relative shallowness of the hormonal changes observed.

Normothermic recirculation reduces primary graft dysfunction of kidneys obtained from non-heart-beating donors

Our aim was to analyze the short- and long-term function of kidneys procured from non- heartbeating donors (NHBD) by means of three techniques: in situ perfusion (ISP), total body cooling (TBC) and normothermic recirculation (NR). Fifty-seven potential NHBD were included. Mean warm ischemia time was 68.9 +/- 35.6 min. Forty-four kidneys were obtained from donors perfused with ISP, 8 with TBC, and 8 with NR. Eighteen kidneys (32%) started functioning immediately, 29 (52%) showed delayed graft function (DGF) and 9 (16%) showed primary non function (PNF). The actuarial graft survival rate was 76.4% at 1 year and 56% at 5 years. The patient survival rate was 89.3% at 5 years. Incidence of DGF and PNF was significantly lower in kidneys perfused with NR than those with ISP or TBC (P < 0.01). Duration of DGF was shorter in kidneys obtained through TBC than in kidneys obtained with ISP (P < 0.05). In conclusion, NR reduces the incidence of DGF and may be considered the method of choice for kidney procurement from NHBD.

[Giant ethmoid neurinoma with intracranial extension]

The schwannomas are tumors arising from nervous tissue. It appears very rarely in the nose and paranasal sinuses. Intra and extracraneal extension of these tumors are even more uncommon. In this paper we report a case of a esfeno-ethmoidal schwannoma with anterior skull fossa extension. We describe the CT scan and magnetic resonance imaging and the histological features. Surgical resection was carried through a craniofacial approach. Some data about diagnosis, treatment and outcome of these tumors are revised.

Orphanin-FQ/nociceptin inhibits kindling epileptogenesis and enhances hippocampal feed-forward inhibition

The role of Orphanin-FQ/nociceptin in synaptic plasticity was assessed by its potency in modulating kindling epileptogenesis in vivo, and feed-forward inhibition in hippocampal recordings in vitro. In addition, a specific rabbit antiserum against this peptide was obtained and the immunohistochemical distribution of nociceptin was determined in rat brain slices. After the establishment of kindling epilepsy, by daily electrical stimulation of the piriform cortex, the i.c.v. injection of nociceptin, 20 min before the kindling stimulation, was not able to block the generation of the generalized seizures, nor to alter their duration. However, the i.c.v. injection of nociceptin, 20 min before each stimulation along the kindling process, depressed its development in a dose-dependent manner. This effect was specific since the nociceptin antagonist [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2, but not the broad-spectrum opiate antagonist, naloxone, was able to completely block nociceptin actions. The inhibitory role of nociceptin was assessed by in vitro recordings from entorhinal cortex-hippocampal slices. By single pulses applied over the Schaffer collaterals, we found that synaptic transmission was facilitated onto CA1, but using a paired-pulse protocol, we found that nociceptin potentiated feed-forward inhibition. The immunohistochemical data show that nociceptin is expressed in limbic cortical regions, including the piriform cortex and the hippocampus. Our results demonstrate that nociceptin exerts a modulatory role in limbic excitability and suggest that it provides an inhibitory control in the development of epilepsy by possibly inhibiting the spread of excitation through the system, by favoring feed-forward inhibition.

Seizures induce simultaneous GABAergic and glutamatergic transmission in the dentate gyrus-CA3 system

Monosynaptic and polysynaptic responses of CA3 pyramidal cells (PC) to stimulation of the dentate gyrus (DG) are normally blocked by glutamate receptor antagonists (GluRAs). However, after kindled seizures, GluRAs block the monosynaptic excitatory postsynaptic potential (EPSP) and isolate a monosynaptic inhibitory postsynaptic potential (IPSP), suggesting that mossy fibers release GABA. However, kindling epilepsy induces neuronal sprouting, which can underlie this fast inhibitory response. To explore this possibility, the synaptic responses of PC to DG stimulation were analyzed in kindled epileptic rats, with and without seizures, and in nonepileptic rats, immediately after a single pentylenetetrazol (PTZ)-induced seizure, in which sprouting is unlikely to have occurred. Excitatory and inhibitory synaptic responses of PC to DG stimulation were blocked by GluRAs in control cells and in cells from kindled nonseizing rats, confirming that inhibitory potentials are disynaptically mediated. However, a fast IPSP could be evoked in kindled epileptic rats and in nonepileptic rats after a single PTZ-induced seizure. The same response was induced after rekindling the epileptic nonseizing rats. This IPSP has an onset latency that parallels that of the control EPSP and is not altered under low Ca(2+) medium or halothane perfusion. In addition, it was reversibly depressed by L(+)-2-amino-4-phosphonobutyric acid (L-AP4), which is known to inhibit transmitter release from mossy fibers. These results demonstrate that seizures, and not the synaptic rearrangement due to an underlying epileptic state, induce the emergence of fast inhibition in the DG-CA3 system, and suggest that the mossy fibers underlie this plastic change.