Improved dynamic connection detection power in estimated dynamic functional connectivity considering multivariate dependencies between brain regions

To estimate dynamic functional connectivity (dFC), the conventional method of sliding window correlation (SWC) suffers from poor performance of dynamic connection detection. This stems from the equal weighting of observations, suboptimal time scale, nonsparse output, and the fact that it is bivariate. To overcome these limitations, we exploited the kernel‐reweighted logistic regression (KELLER) algorithm, a method that is common in genetic studies, to estimate dFC in resting state functional magnetic resonance imaging (rs‐fMRI) data. KELLER can estimate dFC through estimating both spatial and temporal patterns of functional connectivity between brain regions. This paper compares the performance of the proposed KELLER method with current methods (SWC and tapered‐SWC (T‐SWC) with different window lengths) based on both simulated and real rs‐fMRI data. Estimated dFC networks were assessed for detecting dynamically connected brain region pairs with hypothesis testing. Simulation results revealed that KELLER can detect dynamic connections with a statistical power of 87.35% compared with 70.17% and 58.54% associated with T‐SWC (p‐value = .001) and SWC (p‐value <.001), respectively. Results of these different methods applied on real rs‐fMRI data were investigated for two aspects: calculating the similarity between identified mean dynamic pattern and identifying dynamic pattern in default mode network (DMN). In 68% of subjects, the results of T‐SWC with window length of 100 s, among different window lengths, demonstrated the highest similarity to those of KELLER. With regards to DMN, KELLER estimated previously reported dynamic connection pairs between dorsal and ventral DMN while SWC‐based method was unable to detect these dynamic connections.     

Retrograde Parotidectomy and facial nerve outcomes: A case series of 44 patients

Purpose

The most common surgical method to remove benign parotid tumors remains the prograde approach. We examined if a retrograde surgical technique offers better outcomes than historical prograde controls.

Neurotrophic factor GDNF promotes survival of salivary stem cells

Stem cell–based regenerative therapy is a promising treatment for head and neck cancer patients that suffer from chronic dry mouth (xerostomia) due to salivary gland injury from radiation therapy. Current xerostomia therapies only provide temporary symptom relief, while permanent restoration of salivary function is not currently feasible. Here, we identified and characterized a stem cell population from adult murine submandibular glands. Of the different cells isolated from the submandibular gland, this specific population, Lin^–CD24⁺c-Kit⁺Sca1⁺, possessed the highest capacity for proliferation, self renewal, and differentiation during serial passage in vitro. Serial transplantations of this stem cell population into the submandibular gland of irradiated mice successfully restored saliva secretion and increased the number of functional acini. Gene-expression analysis revealed that glial cell line–derived neurotrophic factor (Gdnf) is highly expressed in Lin^–CD24⁺c-Kit⁺Sca1⁺ stem cells. Furthermore, GDNF expression was upregulated upon radiation therapy in submandibular glands of both mice and humans. Administration of GDNF improved saliva production and enriched the number of functional acini in submandibular glands of irradiated animals and enhanced salisphere formation in cultured salivary stem cells, but did not accelerate growth of head and neck cancer cells. These data indicate that modulation of the GDNF pathway may have potential therapeutic benefit for management of radiation-induced xerostomia.     

Total versus subtotal thyroidectomy for the management of benign multinodular goiter in an endemic region

BACKGROUND: Because controversy still continuous to surround use of total thyroidectomy for the management of benign multinodular goiter, the present study aims to prospectively compare the safety and efficacy of total thyroidectomy with subtotal thyroidectomy. METHODS: A total of 200 consecutive patients with benign multinodular goiter were assigned to have either total thyroidectomy (n = 105) or subtotal thyroidectomy (n = 95) based on preoperative evaluation, intraoperative macroscopic findings and nodular dissemination. The patients with no healthy tissue or nodules localized in the dorsal part of the gland, which are usually left during normal subtotal resection, were assigned to the total thyroidectomy group. Demographic details, biochemical findings, indications for operation, operating time, specimen weight, complications and hospital stay were noted. RESULTS: There was no significant difference in the sex, hormonal status or duration of goiter between the two groups (P = 0.74, P = 0.59 and P = 0.59, respectively). The mean operating time was longer (148.52 min +/- 51.10 vs 135.10 min +/- 32.47, P = 0.03), and the mean weight of the specimens was greater (228.40 g +/- 229.91 vs 157.01 g +/- 151.23, P = 0.01) for total rather than subtotal thyroidectomy. Either temporary recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism occurred in 10 (9.3%) or 12 (11.4%) of the patients undergoing total compared with six (6.3%) or nine (9.5%) of the patients undergoing subtotal thyroidectomy (P = 0.40 and P = 0.65, respectively). Either permanent RLN palsy or hypoparathyroidism was observed in one patient undergoing total thyroidectomy (P = 0.34 for each comparison). The mean hospital stay was longer in the total thyroidectomy group (2.24 days +/- 1.18 vs 1.89 days +/- 0.72 for subtotal thyroidectomy, P = 0.01). CONCLUSIONS: The present study shows that total thyroidectomy can be performed without increasing risk of complication, and it is an acceptable alternative for benign multinodular goiter, especially in endemic regions, where patients present with a huge multinodular goiter.     

The comparison of the efficacy of scoring systems in organophosphate poisoning

The purpose of this study was to evaluate the impact of the Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) II scoring systems for organophosphate poisoning (OPP) in an intensive care unit (ICU). The following data were collected on all consecutive patients who were admitted to the ICU between June 1999 and December 2004. Demographic data, GCS, APACHE II and SAPS II scoring systems were recorded. Predicted mortality was calculated using original regression formulas. Standardized mortality ratio (SMR) was computed with 95% confidence intervals (CI). The sensitivity and specificity for each scoring system were evaluated by calculating the Area Under the Receiver Operating Characteristic Curves. The actual mortality in OPP was 21.9%. Predicted mortality by all systems was not significantly different from actual mortality [SMR and 95% CI for GCS: 1.00 (0.65 1.35), APACHE II: 0.87 (0.54-1.03), SAPS II: 1.40 (0.98-1.82)]. The area under the ROC curve for APACHE II is largest, but there is no statistically significant difference when compared with SAPS II and GCS (GCS 0.900 +/- 0.059, APACHE II 0.929 +/- 0.045 and SAPS II 0.891 +/- 0.057). In our ICU group of patients, in predicting the mortality rates in OPP, the three scoring systems, which are GCS, APACHE II and SAPS II, had similar impacts; however, GCS system has superiority over the other systems in being easy to perform, and not requiring complex physiologic parameters and laboratory methods.     

Marker retention in the cochlea following injections through the round window membrane

Local delivery of drugs to the inner ear is increasingly being used in both clinical and experimental studies. Although direct injection of drugs into perilymph appears to be the most promising way of administering drugs quantitatively, no studies have yet demonstrated the pharmacokinetics in perilymph following direct injections. In this study, we have investigated the retention of substance in perilymph following a single injection into the basal turn of scala tympani (ST). The substance injected was a marker, trimethylphenylammonium (TMPA) that can be detected in low concentrations with ion-selective microelectrodes. Perilymph pharmacokinetics of TMPA was assessed using sequential apical sampling to obtain perilymph for analysis. The amount of TMPA retained in perilymph was compared for different injection and sampling protocols. TMPA concentrations measured in fluid samples were close to those predicted by simulations when the injection pipette was sealed into the bony wall of ST but were systematically lower when the injection pipette was inserted through the round window membrane (RWM). In the latter condition, it was estimated that over 60% of the injected TMPA was lost due to leakage of perilymph around the injection pipette at a rate estimated to be 0.09muL/min. The effects of leakage during and after injections through the RWM were dramatically reduced when the round window niche was filled with 1% sodium hyaluronate gel before penetrating the RWM with the injection pipette. The findings demonstrate that in order to perform quantitative drug injections into perilymph, even small rates of fluid leakage at the injection site must be controlled.     

Value of procalcitonin in differentiating post-surgical systemic and infectious complications from inflammatory reaction caused by surgical trauma in fracture surgery: preliminary report

Effect of fracture itself and fracture surgery to serum procalcitonin levels and the value of procalcitonin in differentiating inflammatory reaction caused by fracture surgery from post-surgical complications were investigated in this study. Twenty-nine patients over 50 years old who underwent surgery for hip fractures were evaluated. Procalcitonin, C-reactive protein, white blood cell count and body temperature were measured before surgery and for 5 days postoperatively. Preoperatively, procalcitonin levels were lower than the normal in all patients. It made a peak on the first postoperative day without exceeding the normal range and returned to preoperative level on the fifth day. In contrast to C-reactive protein, which was above the normal in all patients, procalcitonin levels were higher than the normal only in patients with systemic and infectious complications. Procalcitonin seems to be much superior to other infection parameters based on the fact that it is not affected by inflammatory response resulting from fracture itself and fracture surgery, it provides a faster response to surgical trauma, it declines more rapidly after removal of the factor leading to the inflammatory response, it follows a standard postoperative kinetics. It has to be a warning sign for systemic and infectious complications, when postoperative procalcitonin levels have been above 0.5 ng/ml.