Ozlem Celebi

Short latency afferent inhibition in Parkinson's disease patients with dementia†

Cortical cholinergic deficiency occurs in Parkinsons disease (PD) and is more severe in PD dementia (PDD). Short‐latency afferent inhibition (SAI) can be used as an in vivo test for the evaluation of the cholinergic circuit in the cerebral motor cortex.

Default mode network connectivity is linked to cognitive functioning and CSF Aβ1–42 levels in Alzheimer’s disease

BACKGROUND Changes in the default mode network (DMN) activity are early features of Alzheimers disease (AD) and may be linked to AD-specific Aβ pathology. METHODS Cognitive profiles; DMN connectivity alterations; and cerebrospinal fluid (CSF) amyloid beta (Aβ)1-42, total tau, phosphorylated tau 181, and α-synuclein levels were studied in 21 patients with AD and 10 controls. RESULTS DMN activity is altered in AD. Posterior cingulate cortex (PCC) functional connectivity with other parts of DMN was related to cognitive function scores. The reduction of connectivity of the dorsal PCC with the retrosplenial cortex on the right side was closely related to decreased CSF Aβ1-42 levels in patients with AD. CONCLUSIONS The dorsal PCC and retrosplenial cortex may have special importance in the pathogenesis and cognitive findings of AD.

Detection of O6-methylguanine-DNA methyltransferase gene promoter region methylation pattern using pyrosequencing and the effect of methylation pattern on survival, recurrence, and chemotherapy sensitivity in patients with laryngeal cancer

AIM To determine the methylation pattern of the promoter region of the O6-methylguanine-DNA methyltransferase (MGMT) gene in laryngeal cancer and normal laryngeal mucosa samples using pyrosequencing, and to determine the relationship between the methylation pattern of MGMT, and tumor stage, survival, recurrence, and chemosensitivity in patients with laryngeal cancer. MATERIALS AND METHODS Laryngeal cancer and normal laryngeal mucosa specimens were obtained from our paraffin block archives, and then subjected to pyrosequencing. Different cut-off values were used to detect methylation. Clinicopathological data for the patients that provided specimens were obtained from archive records. RESULTS When 5% was used as the cut-off value, 78% of the laryngeal cancer specimens (64 of 82), and 27.3% of normal laryngeal mucosa specimens (3 of 11) were considered methylated. When 10% was used as the cut-off value, 47% of the laryngeal cancer specimens (39 of 82), and none of the normal laryngeal mucosa specimens were considered methylated. There was not a significant relationship between the methylation status of MGMT, and clinicopathological parameters, including age, tumor stage, histopathological differentiation, chemoradiotherapy protocol used, recurrence, or disease-free survival. CONCLUSION Pyrosequencing is a reliable semiquantitative technique that can be used to detect the methylation pattern. Methylation was common in the laryngeal cancer specimens, but there was not a significant relationship between the methylation status of MGMT and clinicopathological parameters.

Human papillomavirus infection in patients with laryngeal carcinoma

BackgroundThe aim of this study was to determine the HPV positivity rate in patients with laryngeal cancer, and to determine the effect of HPV positivity on survival. An additional aim was to determine if patients with HPV positive laryngeal cancer are more sensitive to chemotherapy and if such sensitivity differs according to chemotherapy protocol.MethodsThe study included laryngeal specimens obtained from 82 laryngeal cancer patients and 11 laryngeal specimens with normal laryngeal mucosa that were obtained from our hospital’s paraffin block archives between 1995 and 2013. HPV was detected via chromogenic in situ hybridization (cISH) and confirmed via genotyping.ResultsHPV was not detected in any of the 82 laryngeal cancer patients’ laryngeal specimens, nor in any of the 11 archived laryngeal specimens with normal laryngeal mucosa via cISH. Genotyping confirmed these findings; none of the HPV types studied were detected in any of the specimens. As none of the study samples were HPV positive, it was not possible to compare survival, recurrence, or chemotherapy sensitivity.ConclusionsHPV infection is not a leading cause of laryngeal cancer; however, additional research on HPV positivity in patients with laryngeal cancer and its effect on recurrence, survival, and chemotherapy sensitivity is warranted.

DEFAULT-MODE NETWORK FUNCTIONAL CONNECTIVITY CHANGES IN ALZHEIMER'S DISEASE

and p 181 -tau (R1⁄4 0.48; p1⁄4 0.017), but not A b 42. Lactate was not correlated with any CSF biomarker. The Figure depicts estimatedmarginal means and standard errors from the mixed model.Conclusions: Patients with early AD have higher glucose concentration in an area susceptible to AD pathology compared to controls, perhaps as a result of lower glucose utilization due to neurogeneration. In addition, lactate concentration is higher, suggesting higher regional metabolic reliance on glycolysis. These results motivate the longitudinal study of MRS glucose and lactate as novel AD biomarkers. Acknowledgement: This research was supported entirely by the Intramural Research Program of the NIA/NIH.

The Nose and the Eustachian Tube

Normal functioning of the ear is closely related to the health status of the nose and paranasal sinuses. Pathologies of the nose, sinuses, and nasopharynx play an important role in the cause, treatment, and sequelae of ear disease. Sniffing creates negative pressure in the nose, in the nasopharynx, and in the middle ear, causing middle ear pathologies in patients with hyperpatent eustachian tube. Nose blowing increases intranasal propelling viscous fluid into the paranasal sinuses and middle ear. Sneezing elevates intranasal pressure tenfold times less compared to nose blowing. However, sneezing while the nasal passages are blocked may lead to an increase in nasopharyngeal pressure, causing a failure of the valve which protects the entrance to the eustachian tube. The positive middle ear pressures with bilateral nasal obstruction are caused by tubal openings synchronized into the positive phase of nasopharyngeal pressure generation. Increase in the environmental pressure in the presence of nasal obstruction interferes with eustachian tube functioning; thus, the tube may remain closed and may be “locked.” Continued increase causes barotrauma.