Differential effects of bupivacaine enantiomers,ropivacaine and lidocaine on up-regulation of cell surface voltage-dependent sodium channels in adrenal chromaffin cells

In cultured bovine adrenal chromaffin cells, (+/-)-bupivacaine inhibited veratridine-induced 22Na(+) influx (IC(50) 6.8 microM). The IC(50) of (+)-bupivacaine (2.8 microM) was 6.2-, 7.4-, and 17.1-fold lower than those of (-)-bupivacaine (17.3 microM), (-)-ropivacaine (20.6 microM), and lidocaine (47.8 microM). Chronic (i.e. 3-h) treatment of cells with (+/-)-bupivacaine increased cell surface [3H]saxitoxin ([3H]STX) binding capacity by 48% (EC(50) of 233 microM; t(1/2)=7.4 h), without changing the K(d) value. Treatment for 24 h with either (+)- or (-)-bupivacaine, or (-)-ropivacaine elevated [3H]STX binding, whereas 24-h treatment with lidocaine had no effect. The rise of [3H]STX binding by (+/-)-bupivacaine was prevented by cycloheximide, an inhibitor of protein synthesis, or brefeldin A, an inhibitor of cell surface vesicular exit from the trans-Golgi network; however, (+/-)-bupivacaine did not increase Na(+) channel alpha- and beta(1)-subunit mRNA levels. In cells subjected to (+/-)-bupivacaine treatment (1 mM for 24 h) followed by 3-h washout, veratridine-induced 22Na(+) influx was enhanced, even when measured in the presence of ouabain, an inhibitor of Na(+),K(+)-ATPase. Ptychodiscus brevis toxin-3 potentiated veratridine-induced 22Na(+) influx by 2.3-fold in the (+/-)-bupivacaine-treated cells, as in non-treated cells. These results suggest that lipophilic bupivacaine enantiomers or (-)-ropivacaine acutely inhibit Na(+) channel gating, whereas its chronic treatment up-regulates cell surface expression of Na(+) channels via translational and externalization events.     

Rhabdomyoma of the base of the tongue

The histopathological and imaging findings of a rhabdomyoma of the base of the tongue were studied. An immunohistochemical examination of the tumour cells showed positive immunostaining for myoglobin, desmin, and striated muscle actin, but negative immunostaining for smooth muscle actin. Electron microscopy showed many glycogen granules and mitochondria in the tumour cells. The T2-weighted and contrast-enhanced magnetic resonance images (MRI) clearly delineated morphological features of this tumour, but T1-weighted MRI and computed tomography (CT) images showed no important features. These findings are typical for an adult extracardiac rhabdomyoma located in the head and neck region, and they will be useful for diagnosis of this tumour.     

Late laryngo-tracheal cartilage necrosis with external fistula 44 years after radiotherapy

Major late complications, following radiotherapy of head and neck carcinomas, such as laryngeal oedema, perichondritis and chondronecrosis usually occur between three and 12 months after treatment. However, the present case displayed necrosis of the laryngo-tracheal cartilage and ulceration of anterior neck skin with a tracheal fistula 44 years after irradiation. The reasons for the long interval between irradiation and late complications may be explained by long-standing hypovascularity and/or infection of the irradiated area. Histological study revealed chondronecrosis without inflammatory cells in the laryngo-tracheal cartilage and bacterial colonization of subcutaneous tissue. Necrotic tissue was removed and tracheostomy was performed. The fistula was almost completely closed using a delto-pectoral cutaneous flap and the clinical course of patient has been good. This paper demonstrates the possibility of laryngo-tracheal necrosis in cases that had received radiation as long ago as 44 years.     

Relationship between the local stiffness of the outer hair cell along the cell axis and its ultrastructure observed by atomic force microscopy

As electromotility may arise from a conformational change of the molecules' 'protein motors', which might be distributed along the outer hair cell (OHC) lateral wall, the force generated by the OHC electromotility would be related not only to the conformational change of the protein motors but also to the mechanical properties of the lateral wall. Therefore, a detailed understanding of the mechanical properties of the OHC lateral wall is important. In our previous reports, to understand the difference in the stiffness along the cell axis, the local deformation of the OHC in response to hypotonic stimulation was analyzed by measuring the displacement of microspheres attached randomly to the cell lateral wall, and the distribution of Young's modulus along the cell axis was obtained using the contact mode of an atomic force microscope (AFM). These investigations revealed that the stiffness of the cell in the apical region was greater than that in other regions where the stiffness is constant. In this study, the ultrastructure of the OHC lateral wall was investigated with the oscillation imaging mode of the AFM (Tapping Mode), and the relationship between the stiffness along the cell axis and the ultrastructure that was observed by the AFM imaging was analyzed. From the analysis, it was concluded that the circumferential filaments observed in the tapping mode AFM are actins which are part of the cortical lattice, and that the difference between the intervals of the circumferential filaments in the apical region and those in other regions is one factor that causes the high stiffness in the apical region.     

Lidocaine spray used to capture a live Clinostomum parasite causing human laryngitis

This case report describes a patient who developed Clinostomum laryngitis after eating raw fresh-water fish. Parasite removal was performed under general anesthesia using a laryngomicroscopic method. Because it was difficult to capture the worm intact using forceps, it was sprayed with 8% lidocaine solution. This immediately inhibited peristaltic movement of the parasite allowing easy retrieval without tearing any part of the organism, thus facilitating parasite identification.     

Ultrastructural localization of aminopeptidase A/angiotensinase and placental leucine aminopeptidase/oxytocinase in chorionic villi of human placenta

AIMS: Membrane-bound aminopeptidases in human placenta are thought to be involved in maintaining homeostasis during pregnancy by metabolizing bioactive peptides such as oxytocin and angiotensin at the interface between the fetus and mother. Because determining the precise localization of these enzymes is required to support this notion, we investigated the ultrastructural localization of two principal enzymes, aminopeptidase A (APA; EC 3.4.11.7)/angiotensinase and placental leucine aminopeptidase (P-LAP; EC 3.4.11.3)/oxytocinase in human first trimester and full-term placenta. METHODS: Immunohistochemical analysis using anti-P-LAP and anti-APA antibodies was performed on ultrathin frozen sections of fixed human placental villi. RESULTS: Transmission immunoelectron microscopy revealed that both enzymes were expressed on the surface of apical microvilli of syncytiotrophoblast cells and, to a lesser extent, on the basal infoldings. The location of the two enzymes did not vary between the first trimester and full-term placenta sections, while the staining intensities were slightly enhanced in full-term villi. CONCLUSIONS: Our observation that P-LAP and APA are present on the microvilli, which is a site of interaction between the mother and fetus, suggests possible involvement of these enzymes in cleaving peptide hormones from the fetus and mother in order to regulate bioactivity.     

Binding of immunoglobulin G antibodies in Guillain-Barré syndrome sera to a mixture of GM1 and a phospholipid: possible clinical implications

Anti-GM1 immunoglobulin G (IgG) antibodies are frequently present in sera from patients with Guillain-Barré syndrome (GBS). A previous report on a patient who had a neuropathy with immunoglobulin M (IgM) M-protein binding to a conformational epitope formed by phosphatidic acid (PA) and gangliosides prompted us to investigate the binding of IgG antibodies in GBS sera to a mixture of GM1 and PA (GM1/PA). Of 121 GBS patients, 32 had anti-GM1 IgG antibodies. All 32 also had antibody activity against GM1/PA. Twenty-five (78%) of 32 patients had greater activity against GM1/PA than against GM1 alone. Twelve patients who had no anti-GM1 IgG antibodies had IgG antibody activity against GM1/PA. No GBS patient had IgG antibody against PA alone. In contrast, two rabbit anti-GM1 antisera had greater activity against GM1 alone than against GM1/PA. IgG antibody with greater binding activity against a mixture of GM1 and a phospholipid than against GM1 alone may have an important role in the pathogenesis of GBS and has implications for diagnosis.     

Expression of the receptor for pituitary adenylate cyclase-activating polypeptide (PAC1-R) in reactive astrocytes

We generated transgenic mice that express an enhanced green fluorescent protein (EGFP) under the control of the mouse glial fibrillary acidic protein (GFAP) promoter. In one of the transgenic lines, the green fluorescence of EGFP was undetectable in almost all of the brain regions, including the neocortex, in untreated animals. However, when reactive astrogliosis was induced by cortical stab wounding, the strong fluorescence of EGFP was observed around the needle track but was not found in the corresponding area of the contralateral hemisphere. The EGFP-expressing cells had the morphological features of reactive astrocytes such as thick processes. The EGFP-expressing cells were found to overlap with the astroglial marker GFAP, but not with the microglial marker CD11b or the neuronal marker NeuN. Furthermore, there were some EGFP-expressing cells that expressed vimentin-like immunoreactivity, the specific marker for reactive astrocytes. These results strongly suggest that the EGFP-expressing cells are reactive astrocytes, but not resting astrocytes. Using these transgenic mice, immunostaining for the PAC1 receptor (PAC1-R) was performed. PAC1-R, which is a pituitary adenylate cyclase-activating polypeptide (PACAP)-specific receptor, binds PACAP, which is known to have a wide variety of functions. An immunohistochemical study revealed the localization of PAC1-R in reactive astrocytes visualized with EGFP around the needle track at 5 days postsurgery.