TrkB receptor interacts with mGlu2 receptor and mediates antipsychotic-like effects of mGlu2 receptor activation in the mouse

Metabotropic glutamate receptor 2 (mGlu2) attracts particular attention as a possible target for a new class of antipsychotics. However, the signaling pathways transducing the effects of mGlu2 in the brain remain poorly characterized. Here, we addressed this issue by identifying native mGlu2 interactome in mouse prefrontal cortex. Nanobody-based affinity purification and mass spectrometry identified 149 candidate mGlu2 partners, including the neurotrophin receptor TrkB. The later interaction was confirmed both in cultured cells and prefrontal cortex. mGlu2 activation triggers phosphorylation of TrkB on Tyr816 in primary cortical neurons and prefrontal cortex. Reciprocally, TrkB stimulation enhances mGlu2-operated Gi/o protein activation. Furthermore, TrkB inhibition prevents the rescue of behavioral deficits by glutamatergic antipsychotics in phencyclidine-treated mice. Collectively, these results reveal a cross-talk between TrkB and mGlu2, which is key to the behavioral response to glutamatergic antipsychotics.

Apnoeic and obstructive nonapnoeic sleep respiratory events

Obstructive nonapnoeic event (ONE) scoring is shrouded in confusion. This is important in patients with mild disease, in whom precision is crucial. The aims of the present study were: 1) to identify ONEs using oesophageal pressure (OP) (OP-ONEs) and a noninvasive (NI) method (NI-ONEs); 2) to compare both methods of scoring; and 3) to determine the contribution of ONE definitions to clinical findings. Patients with suspected sleep apnoeas (respiratory disturbance index <or=10) during a first polysomnography were subjected to a second with an OP measurement. OP-ONEs and NI-ONEs were defined as an increase in OP or discernible reduction in the amplitude of thoracoabdominal bands with both desaturation and/or arousal. Bland-Altman analysis established agreement. Comparisons were made between OP-ONEs, NI-ONEs and clinical findings. In our sample (n = 90), the addition of an arousal to the NI-ONEs or OP-ONEs with only desaturation increased the number of NI-ONEs by 329 and 362%, respectively. NI-ONEs with arousal and/or desaturation detected 91% of OP-ONEs. The association with sleepiness depended on the incorporation of arousal into the definition of ONEs. In patients with mild disease, the addition of an arousal to ONEs, with only desaturation, markedly increased respiratory disturbance index, with probable therapeutic implications. Scoring respiratory events as apnoea and ONEs is easier and sufficiently accurate.

The obesity hypoventilation syndrome can be treated with noninvasive mechanical ventilation

STUDY OBJECTIVES

To assess the effectiveness of nasal noninvasive mechanical ventilation (NIMV) in patients with obesity hypoventilation syndrome (OHS).

DESIGN

Clinical assay that compares two groups of patients with hypercapnic respiratory failure, one group with OHS and the other group with kyphoscoliosis, in their basal situation and after 4 months of treatment with nocturnal NIMV. Thirty-six patients (22 patients with OHS and 14 patients with kyphoscoliosis) completed the study protocol.

RESULTS

The frequency of symptoms, such as morning headache, morning drowsiness, dyspnea, and leg edema, improved in a statistically significant way in both groups of patients. The sleepiness improved only in the group with OHS. The comparison of frequency of symptoms between both groups of patients after NIMV treatment did not present statistically significant differences. In the resting situation and without nasal ventilation in place, the PO(2) (mean +/- SD) changed from 51 +/- 10 to 64 +/- 11 mm Hg (p < 0.001) and PCO(2) from 58 +/- 10 to 45 +/- 5 mm Hg (p < 0.001) when the patients with OHS were treated with NIMV. In the group of patients with kyphoscoliosis, likewise without nasal ventilation in place, PO(2) changed from 53 +/- 6 to 65 +/- 5 mm Hg (p < 0.001) and PCO(2) from 59 +/- 11 to 45 +/- 4 mm Hg (p < 0.001) with NIMV treatment. When we compared PO(2) and PCO(2) in both groups of patients at the beginning and at the end of NIMV treatment, we did not find statistically significant differences between OHS and kyphoscoliosis.

CONCLUSIONS

NIMV improves the clinical symptoms and the respiratory failure of patients with OHS to a similar degree to that reported for diseases in which its use is completely established, such as kyphoscoliosis. Therefore, NIMV could be an alternative to the treatment of patients with OHS.

[Usefulness of transbronchial punction and mediastinoscopy in mediastinal nodal staging of non-microcytic bronchogenic carcinoma. Preliminary study]

Preliminary study to compare the sensitivity and specificity of transbronchial needle aspiration (TBNA) and mediastinoscopy/anterior mediastinotomy (MED/AMED) and/or thoracotomy for staging of mediastinal nodes in non-small cell carcinoma. To determine the sensitivity and specificity of computerized tomography (CT) as a screening technique. Thirty-three patients with non-small cell carcinoma but no remote metastasis and good lung function were evaluated. A chest CT scan was performed before bronchoscopy in 27 patients and before surgery in the others. Nodular areas considered diseased based on CT images were staged by TBNA. When CT images were not available before bronchoscopy. TBNA for staging was performed in the subcarinal region. Results by TBNA were compared with those obtained by MED/AMED and/or thoracotomy. The prevalence of metastatic nodular disease was 47%. CT detected enlarged mediastinal nodes in 24 patients; the images were considered normal in 9 patients. Sensitivity and specificity of CT was 93% and 54%, respectively, with a positive predictive value (PPV) of 68% and negative predictive value (NPV) of 87.5%. The sensitivity and specificity of MED/AMED were 73% and 100%, respectively; PPV was 100% and NPV was 75%. The sensitivity and specificity of TBNA were 36% and 92%, respectively; PPV was 83% and NPV was 57%. The pneumothorax with pleural empyema suffered by one patient after MED could have been avoided, given that the earlier TBNA was positive. TBNA is a safe, useful technique for staging nodes in non-small cell carcinoma. Although the sensitivity of TBNA is lower than that of MED, regions that are difficult to reach with the latter technique can be sampled by TBNA. Furthermore, MED can be rendered unnecessary by positive TBNA results. CT imaging of the chest is sensitive but its specificity is low for detecting ganglial metastasis.

Noninvasive positive pressure ventilation and not oxygen may prevent overt ventilatory failure in patients with chest wall diseases

Some patients with chest wall diseases (CWD) without respiratory failure manifest important alterations in nocturnal gas exchange, as a previous stage to the future development of daytime respiratory failure. The purpose of this study was to evaluate the efficacy of nasal intermittent positive pressure ventilation (NIPPV) during sleep in a group of obese patients and in another group with restrictive thoracic diseases (RTD), comparing the results with those obtained from conventional nocturnal oxygen therapy. From a total of 42 patients with CWD free of daytime respiratory failure, 27 (64%) were considered nocturnal oxygen desaturators without sleep apnea and were included in the study. The study protocol was completed by 21 of these patients. After 2 weeks of treatment, symptoms of dyspnea, morning headaches, and morning obnubilation improved significantly (p<0.05) in both groups of patients after NIPPV but not with oxygen. Baseline daytime PaO2 was 68+/-7 mm Hg in the obese group of patients and 73+/-11 mm Hg in the RTD group. It improved significantly with NIPPV to 73+/-5 mm Hg in obese patients (p<0.05) and to 77+/-12 mm Hg in the RTD group (p<0.05) but did not change with oxygen (68+/-8 mm Hg in the obese group and 73+/-12 mm Hg in the RTD group). Both treatments improved oxygen saturation during sleep, but oxygenation tends to be higher with oxygen than with NIPPV. Only NIPPV was able to normalize the baseline nocturnal alveolar hypoventilation. From the 21 patients treated, 19 decided to continue with long-term NIPPV, one with oxygen, and one refused treatment. We conclude that in patients with CWD who manifest nighttime oxygen desaturation and hypoventilation, early initiation of NIPPV is preferable to supplemental oxygen. Our results also suggest that NIPPV initiated before overt ventilatory failure could prevent its onset.

Squamous cell carcinoma antigen (SCC Ag) in the diagnosis and prognosis of lung cancer

OBJECTIVE

We have studied the usefulness of squamous cell carcinoma antigen (SCC Ag) in diagnosis and prognosis of lung cancer (LC).

MATERIAL AND METHODS

We have measured the serum SCC Ag levels in 388 subjects: 69 healthy persons; 103 with nonmalignant lung diseases (NMLD); 24 with lung metastasis of extrapulmonary origin (LMEO); and 192 with LC (88, with squamous cell carcinoma [SCC] type). In 55 with SCC, we analyzed the survival time.

RESULTS

Serum SCC Ag was above 2.5 ng/ml in 1.4 percent of healthy persons; 2.9 percent of those with NMLD; 8.3 percent of those with LMEO; and 27.6 percent of those with LC. Such percentage was 47.7 percent in SCC. In this type, there were significant differences according to the extent of disease (61.6 percent in advanced stages, and 26.5 percent in localized stages, p = 0.002). In the other types, the sensitivity was substantially lower. The initial SCC Ag has prognostic significance (p = 0.02) in the univariate analysis, but it loses such significance in a multivariate model, including the stage.

CONCLUSIONS

Therefore, we do not recommend this marker in the clinical management of patients with LC, even it can be useful in the differential diagnosis if used in combination with other markers.

[Oxygen therapy at a hospital. A routine treatment?]

We have studied the use of Oxygen (O2) in our hospital, evaluating the prescription criteria and also the control and degree of therapeutic compliance. The study was completed with an opinion survey to physicians and nurses on different aspects of oxygen-therapy at the hospital. 50 inpatients under treatment with O2 have been studied. Clinical records and therapeutic prescriptions were reviewed. 47 patients had a previous gasometry, of them 44 had Respiratory Insufficiency (RI). 26 patients were controlled during oxygen-therapy: 15 were still on RI and two had their treatment modified. The compliance of treatment was evaluated through a visit in a non regular hour, 18 patients (36%) were not following oxygen therapy. When a new gasometry was performed it was observed that 21 patients (42%) continued in RI. The survey showed that a high number of physicians and nurses consider that oxygen therapy is done inadequately, being this fact attributed to several factors. There are errors in the handling of O2 at the hospital, possible related with the routine associated to an established therapy and also because O2 is a continuous therapy which requires a permanent level of attention both from the health care personnel and from the patient.