Signaling cascades involved in neuroprotection by subpicomolar pituitary adenylate cyclase-activating polypeptide 38

In neuronal/glial cocultures, pituitary adenylate cyclase-activating polypeptide 38 (PACAP38) prevented neuronal death induced by gp120, lipopolysaccharide (LPS), or other toxic agents, but the dose response of the neuroprotective effect is bimodal, with a peak at a subpicomolar concentration and another peak at a subnanomolar to nanomolar concentration. Although the signaling cascade involved in neuroprotection by nanomolar concentration of the peptide has been shown to be mediated by activation of cAMP-dependent protein kinase and subsequent activation of mitogen-activated protein kinase (MAPK), the mechanism for neuroprotection by a subpicomolar level of PACAP38 remains elusive. In the present study, the signaling involved in neuroprotection by subpicomolar PACAP38 was studied in rat neuronal/glial cocultures. Addition of PACAP38 stimulated expression and activation of extracellular signal-related kinase-type MAPK with a peak response at 10⁻¹³ M; greater concentrations of the peptide induced lesser response. cAMP production also increased at subpicomolar levels of PACAP38, but the level remained unchanged at a level four to five times higher than the base level at concentration below 10⁻¹¹ M. cAMP then started increasing again dose-dependently in a range >10⁻¹¹ MPACAP38. Lipopolysaccharide (LPS)-induced neuronal death, indicated by increased release of neuronspecific enolase, was suppressed by PACAP38 in a bimodal fashion. Neuroprotection by 10⁻¹² M PACAP38 was completely abolished by a MAPK kinase-1 inhibitor, PD98059, and also partially suppressed by Rp-cAMP, a cAMP-dependent protein kinase inhibitor. Moreover, neuroprotection by a nanomolar level of PACAP38 was completely suppressed by Rp-cAMP but not affected by PD98059. We conclude that neuroprotection by subpicomolar PACAP38 is mainly mediated by the signaling pathway involving MAPK activation and partially regulated by cAMP-dependent protein kinase activation. Furthermore, PACAP38 stimulated expression of activity-dependent neuroprotective protein (ADNP), with a peak at 10⁻¹³ M. Greater doses of the peptide induced lesser response. However, 10⁻¹³ M PACAP38-stimulated expression of ADNP was not affected by PD98059. This suggests that neuroprotection by subpicomolar PACA38 might be mediated partially by expression of ADNP, but the major events for neuroprotection by subpicomolar PACAP38 remain to be identified.     

Imaging docking and fusion of insulin granules induced by antidiabetes agents: sulfonylurea and glinide drugs preferentially mediate the fusion of newcomer, but not previously docked, insulin granules

Sulfonylurea and glinide drugs, commonly used for antidiabetes therapies, are known to stimulate insulin release from pancreatic beta-cells by closing ATP-sensitive K+ channels. However, the specific actions of these drugs on insulin granule motion are largely unknown. Here, we used total internal reflection fluorescence (TIRF) microscopy to analyze the docking and fusion of single insulin granules in live beta-cells exposed to either the sulfonylurea drug glibenclamide or the glinide drug mitiglinide. TIRF images showed that both agents caused rapid fusion of newcomer insulin granules with the cell membrane in both control and diabetic Goto-Kakizaki (GK) rat pancreatic beta-cells. However, in the context of beta-cells from sulfonylurea receptor 1 (SUR1) knockout mice, TIRF images showed that only mitiglinide, but not glibenclamide, caused fusion of newcomer insulin granules. Compositely, our data indicate that 1) the mechanism by which both sulfonylurea and glinide drugs promote insulin release entails the preferential fusion of newcomer, rather than previously docked, insulin granules, and that 2) mitiglinide can induce insulin release by a mechanism independent of mitiglinide binding to SUR1.     

Carotid artery stenosis with intraluminal thrombus discovered during carotid artery stenting

A 77-year-old man presented with transient motor weakness of the left hand. Cerebral angiography showed 90% stenosis at the origin of the right internal carotid artery. Carotid artery stenting (CAS) was performed 3 weeks later, and a large intraluminal thrombus was found during the procedure. The blood around the thrombus was aspirated using an aspiration catheter under distal protection with a filter wire protection device, and CAS was successfully performed without complications. Although this patient was treated by CAS without complications, carotid stenosis associated with intraluminal thrombus—because it has a high risk of distal embolism—should be carefully diagnosed immediately before CAS.     

Surgical resection of pulmonary metastases from meningioma: Report of a case

Meningiomas rarely metastasize, and little information on pulmonary metastasectomy from meningioma has been documented. We herein report a case of a potentially curative resection for meningioma that metastasized to the lung. A 67-year-old woman was admitted to our hospital because of two masses in the right lung. In 1993, when the patient was 52 years old, she underwent a craniotomy for an atypical meningioma. The meningioma recurred once in the local site and was re-excised in 1997. In 2008, a screening chest X-ray detected two lung nodules in the right lung field. A computed tomographic scan demonstrated round masses with sharp borders, in the right S2 (2.2 cm in diameter) and S4 (1.1 cm in diameter) regions. A whole-body [¹⁸F]2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/CT examination revealed intense focal FDG uptake (maximum standard uptake value [SUV_max] = 6.9) in the larger mass, and weak FDG uptake (SUV_max = 2.3) in the smaller mass. A wedge resection of S2 and a middle lobectomy of the right lung were performed, and the final diagnosis was pulmonary metastases from an intracranial meningioma. The patient is presently doing well 20 months after the surgery without any signs of recurrence. Our case demonstrates that surgery should be considered when pulmonary metastases are deemed completely resectable by a preoperative radiological examination, and that a good clinical outcome can be achieved.     

Intrathoracic chemo-thermotherapy with radiofrequency waves after extrapleural pneumonectomy for malignant pleural mesothelioma

Although multimodal treatment is advocated for malignant pleural mesothelioma (MPM), a standard therapeutic regimen has not been established. This study evaluated the outcome of our aggressive treatment including extrapleural pneumonectomy (EPP) and postoperative intrathoracic chemo-thermotherapy (PICT). Moreover, we assessed the association between the clinical effect and an in vitro chemosensitivity test. Eleven patients with MPM underwent treatment including EPP followed by PICT using 8 MHz radiofrequency waves. In vitro chemosensitivity was examined using the collagen gel droplet embedded culture drug-sensitivity test (CD-DST). Complete resection was performed in nine patients. More than two courses of PICT with sufficient heating were completely performed in seven patients. There was no perioperative mortality. Grade 3 or 4 toxicity was not recognized. The median overall survival was 19 months, and the median local relapse-free survival was 17 months. Local recurrence was recognized in four patients (36.4%). Of these patients, three had received incomplete PICT. Four patients with complete PICT including a CD-DST-sensitive chemoagent did not develop local recurrence. Of three patients who received complete PICT including a CD-DST-resistant chemoagent, one tumor recurred locally. The present multimodal treatment including EPP and PICT is promising in local control for MPM. Furthermore, CD-DST may provide clinically useful information for MPM.     

Nodular pulmonary amyloidosis

A 72-year-old woman with a diagnosis of suspected rheumatoid arthritis was admitted with multiple pulmonary nodules in the bilateral lung field. To obtain a diagnosis, a nodule was resected using video-assisted thoracic surgery. Microscopically, amorphous eosinophilic acellular substances were surrounded by inflammatory infiltrates, which were confirmed to be amyloid deposits by congo red staining. Thus, a diagnosis of pulmonary amyloidosis was obtained. The clinical features and diagnostic process are discussed.     

Differences in chemosensitivity between primary and paired metastatic lung cancer tissues: In vitro analysis based on the collagen gel droplet embedded culture drug test (CD-DST)

Background

To elucidate the differences in chemosensitivity to anticancer drugs between primary and metastatic lesions in non-small cell lung cancer (NSCLC) patients, we examined the in vitro chemosensitivities of surgically resected NSCLC tissues.

Methods

A total of 32 specimens were enrolled: 26 specimens of primary lesions paired with metastases in the lymph node, 3 specimens of primary lesions paired with metastases in the adrenal gland, and 3 specimens of primary lesions paired with metastases in the lung. The collagen gel droplet embedded culture drug test (CD-DST) was applied to examine the sensitivity of the tissues to anticancer drugs, including cisplatin, gemcitabine, vinorelbine, docetaxel and 5-fluorouracil.

Results

The degree of in vitro sensitivity to each anticancer drug varied between the primary and metastatic lesions. The sensitivity of the paired metastatic lesions was significantly lower than that of the primary lesions only for gemcitabine (P=0.029), vinorelbine (P=0.012), and docetaxel (P=0.009). The incidence of cases diagnosed as CD-DST-sensitive among the paired metastatic lesions was significantly lower than that for the primary lesions for vinorelbine (P=0.035) or docetaxel (P=0.022). The difference in the sensitivity to gemcitabine between the primary and paired non-lymphatic metastases was clearer than that between the primary lesion and paired lymph node metastases.

Conclusions

The sensitivities of the paired metastatic lesions to some anticancer drugs were significantly lower than those of the primary lesions. When performing chemotherapy based on CD-DST data using primary tumors from patients with postoperative recurrence, an appropriate regimen can be selected by carefully considering these differences.