Acute and chronic stability of atrial screw-in leads

The purpose of this study was to evaluate the acute and chronic stability of the atrial screw-in lead. In this study, we used CPI model 4165, 4166, and 4266 porous tip screw-in leads in 32 patients (12 for AAI pacing and 20 for DDD pacing). All of these leads were fixed to the free wall of the right atrium and used as the unipolar type. Acute voltage and current thresholds, lead impedance, P-wave amplitude, and chronic threshold were measured. Early and late complications were also investigated. The average acute stimulation thresholds at 0.6 msec pulse width were 0.82 +/- 0.43 V and 1.1 +/- 0.6 mA. Mean lead impedance was 627.2 +/- 83.1 ohms, and mean P wave amplitude was 3.1 +/- 1.1 mV. After an average follow-up period of 32 months (range: 2-72 months), we found the results of the chronic threshold study to be satisfactory. The thresholds were usually below 0.1 msec pulse width with the nominally programmed pacemaker output. Only one patient required a higher output due to an increased threshold. With regard to complications, neither lead dislodgment nor cardiac perforation was observed. In conclusion, acute and chronic thresholds were satisfactory and no serious complications occurred. Therefore the atrial screw-in lead has long-term reliability and stability.     

Coexistence of pyriform sinus fistula, ectopic lingual thyroid, and ectopic cervical thymus

Objective

We report an extremely rare case of coexistence of pyriform sinus fistula, ectopic lingual thyroid, and ectopic cervical thymus.

Case report

A 16-year-old girl with ectopic lingual thyroid had suffered repetitive painful swelling in the left anterior neck. Barium swallow radiography and computed tomography revealed a fistula arising from the pyriform sinus running down to the anterior neck. She underwent transcervical fistulectomy with preservation of the recurrent laryngeal nerve. Histopathological examination of the surgical specimen showed coexisting thymic tissue.

Conclusion

This illustrative case exemplifies the different embryological origin of the thyroid from that of the third and fourth pharyngeal pouch derivatives.     

Spinal epithelioid hemangioendothelioma with epithelioid angiosarcomatous areas

Epithelioid hemangioendothelioma is a distinctive vascular tumor rarely involving bones. We report a case of epithelioid hemangioendothelioma in the cervical spine with angiosarcomatous areas. A 50-year-old female presented with dizziness while walking. A mixed sclerotic and osteolytic or destructive lesion was radiographically disclosed in her upper cervical vertebrae. Histologically, a laminectomy specimen exhibited areas of ordinary epithelioid hemangioendothelioma together with foci of more atypical epithelioid cell proliferation, closely resembling epithelioid angiosarcoma. This phenomenon has been exceptionally described in cases with skeletal lesions, which are typically of low-grade malignancy.This case was presented at the Closed Meeting of the International Skeletal Society, St. Julians, Malta, October 3–5, 2004     

Mechanisms of antidepressants and serotonin (5-HT)-induced glial cell line-derived neurotrophic factor (GDNF) releases in rat C6 gliobrastoma cells]

Recent studies show that neuronal and glial plasticity are important for the therapeutic action of antidepressants. Here, we demonstrated that amitriptyline, a tricyclic antidepressant, significantly increased GDNF mRNA and GDNF release in C6 cells. Furthermore, different classes of antidepressants increased GDNF release, but non-antidepressant psychotropic drugs did not. The amitriptyline-induced GDNF release was completely inhibited by U0126, a mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitor, but was not inhibited by H-89, a protein kinase A inhibitor or calphostin C, a protein kinase C inhibitor. These results suggest that the amitriptyline-induced GDNF release may be regulated through a MEK/MAPK pathway. Next, we examined the effects of monoamines on GDNF release, because antidepressants are known to increase monoamines. 5-HT increased GDNF mRNA and GDNF release, but noradrenaline and dopamine did not. The 5-HT-induced GDNF release was partially, but significantly, blocked by ketanserin, a 5-HT2A receptor antagonist. The 5-HT-induced GDNF release was completely inhibited by U0126, but was not inhibited by H-89 or calphostin C. These results suggest that the 5-HT-induced GDNF release was mediated through a MEK/MAPK pathway and, at least, 5-HT2A receptors. GDNF, as well as other neurotrophic factors, may contribute to explain the therapeutic action of antidepressants and suggest a novel strategy of pharmacological intervention.     

Diffusion-weighted in vivo localized proton MR spectroscopy of human cerebral ischemia and tumor

The apparent diffusion coefficients (ADCs) of water and brain metabolites were determined by proton MR spectroscopy on a clinical MR scanner for healthy volunteers and for pathological changes in cases of acute cerebral infarction and brain tumor. The ADCs of N-acetyl aspartate (NAA) and creatines in tissue involved in acute infarction were decreased compared to normal control values, while in tumors they showed increased values. Since NAA is a neuronal marker, these findings suggest that neuronal cell viscosity changes according to the pathological status of the tissue. The lactate ADC was significantly larger than the values for other major metabolites in cases of ischemia and tumor, suggesting that lactate is present in a different compartment. These results indicate that metabolite diffusion data can be used to reveal changes in the intracellular environment depending on the pathological status.     

Expression of mKirre, a mammalian homolog of Drosophila kirre, in the developing and adult mouse brain

mKirre, a mammalian homolog of the Drosophila kirre, is expressed in bone marrow stromal cells and the brain. Although mKirre has been shown to support the hematopoietic stem cells, little is known about the function of mKirre in the brain. In the present study, to gain insights into the function of mKirre, we investigated the expression pattern of mKirre gene in the developing and adult mouse brain using in situ hybridization. In the adult brain, mKirre mRNA was highly expressed in the olfactory bulb, the piriform cortex, the cochlear nucleus, and the cerebellum. At embryonic day (E) 11.5, we could observe mKirre mRNA in the differentiating zones of various regions, such as the caudate-putamen, the geniculate body, the thalamus, the amygdala, and the brainstem. Its gene expression in these regions at E11.5 also persisted to the adult, in which its expression levels were much less prominent. After birth, we could first observe high expression of mKirre mRNA in the glomerular and mitral layers of the olfactory bulb, the cortical plate of the neocortex, the cochlear nucleus, and the molecular and granule cell layers of the cerebellum. In the hippocampus, its gene expression was first observed in the dentate gyrus at postnatal day 7. The spatiotemporal expression pattern of mKirre mRNA suggests important roles of mKirre in later developmental processes, especially the synapse formation.