Structural Plasticity of the Primary and Secondary Olfactory cortices: Increased Gray Matter Volume Following Surgical Treatment for Chronic Rhinosinusitis

Functional plasticity of the adult brain is well established. Recently, the structural counterpart to such plasticity has been suggested by neuroimaging studies showing experience-dependent differences in gray matter (GM) volumes. Within the primary and secondary olfactory cortices, reduced GM volumes have been demonstrated in patients with olfactory loss. However, these cross-sectional studies do not provide causal evidence for GM volume change, and thereby structural plasticity. Disorders of the peripheral olfactory system, such as chronic rhinosinusitis (CRS), provide an ideal model to study GM structural plasticity, given that patients may experience long periods of olfactory impairment, followed by near complete recovery with treatment. We therefore performed a prospective longitudinal study in patients undergoing surgical treatment for CRS. We used voxel-based morphometry (VBM) to investigate GM volume change in 12 patients (M:F = 7:5; 47.2 ± 14.9 years), 3 months post-op. There was a significant improvement in olfactory function according to birhinal psychophysical testing. We performed a voxel-wise region of interest analysis, with significance corrected for number of regions (p < 0.0036_corr). We found significantly increased post-operative GM volumes within the primary (left piriform cortex, right amygdala) and secondary (right orbitofrontal cortex, caudate nucleus, hippocampal-parahippocampal complex and bilateral temporal poles) olfactory networks, and decreased GM volumes within the secondary network only (left caudate nucleus and temporal pole, bilateral hippocampal-parahippocampal complex). As a control measure, we assessed GM change within V1, S1 and A1, where there were no suprathreshold voxels. To our knowledge, this is the first study to demonstrate GM structural plasticity within the primary and secondary olfactory cortices, following restoration of olfaction.

Verapamil and Collagen-Induced Platelet Reactions- Evidence for a Role for Intracellular Calcium in Platelet Activation

Calcium is considered to have an essential role in various platelet reactions. Using platelets preincubated with Chlortetracycline, a fluorescent divalent cation indicator, and suspended in a calcium free medium, it was shown that collagen-induced intracellular calcium redistribution occurred before the platelet shape change, the release reaction and thromboxane B2 formation. Verapamil, at concentrations which affect intracellular calcium movements, inhibited intracellular calcium redistribution in platelets and the subsequent collagen-induced platelet reactions. Low concentrations of the ionophore A23187 overcame the inhibitory effect of verapamil. These experiments provide evidence that intracellular calcium mobilization is involved in the activation of platelets by collagen. Furthermore, calcium may be released from different cellular pools since platelet secretion, aggregation and thromboxane B2 formation were inhibited at lower concentrations of verapamil than was the platelet shape change.

Effect of the Calcium-Entry Blocking Agent Nifedipine on Activation of Human Platelets and Comparison with Verapamil

The effects of the calcium-entry blocking agent nifedipine on the activation of human platelets by various agonists has been studied and compared with verapamil. Like verapamil, nifedipine inhibited platelet aggregation and secretion caused by collagen, the second phase of ADP-induced aggregation, and aggregation caused by the ionophore A23187. Both agents inhibited the formation of TXB2 from endogenous arachidonate, whereas only nifedipine inhibited platelet aggregation and decreased TXB2 formation caused by exogenous arachidonate without inhibiting uptake. These results indicate that both calcium-blocking agents may be inhibiting the release of arachidonate in platelets by phospholipases, and that nifedipine also inhibits the formation and action of thromboxane A2 in platelets. Epinephrine-induced aggregation was inhibited by low concentrations of verapamil while nifedipine only inhibited aggregation by epinephrine at much higher concentrations. It is suggested that low concentrations of verapamil inhibit epinephrine-induced aggregation by interacting with platelet α-adrenergic receptors, and that higher concentrations of both calcium-blocking agents inhibit platelet responses to other aggregating agents by preventing intracellular calcium mobilization.

Inhibition of Platelet Function by Antiarrhythmic Drugs, Verapamil and Disopyramide

Various cardiovascular drugs such as nitrates and propranolol, used in the treatment of coronary artery disease have been shown to have an antiplatelet effect. We have studied the in vitro effects of two antiarrhythmic drugs, verapamil and disopyramide, and have shown their inhibitory effect on platelet function. Verapamil, a calcium channel blocker, inhibited the second phase of platelet aggregation induced by adenosine diphosphate (ADP) and inhibited aggregation induced by collagen. Disopyramide similarly inhibited the second phase of platelet aggregation caused by ADP and aggregation induced by collagen. Either drug in synergism with propranolol inhibited ADP or collagen-induced platelet aggregation. Disopyramide at high concentrations inhibited arachidonic add whereas verapamil was without effect. Verapamil, but not disopyramide, inhibited aggregation induced by the ionophore A23187.

Lack of Agreement of Chromogenic and Glotting Assays for Factor X and Protein C in Warfarinised Plasma

Coagulation serine proteases can be measured with either a chromogenic substrate assay or a clotting assay using deficient plasmas. It is a concern whether both assays give similar quantitative results, in particular in plasma obtained fiom patients on long term warfarin therapy. If these two assay methods were interchangeable, then the chromogenic substrate assay has the advantages of precision as well as laboratory automation. We used the intraclass correlation coefficient (r1) to assess the agreement between the two methods in measuring factor X and protein C levels in warfarinised plasma. The results indicate that the extent and pattern of agreement of the two methods for the measurement of the two variables in warfarinised plasma are poor, despite high Pearson product moment coefficients of correlation.

Altered Fibrinolysis in DVT: Influence of Site of Sampling

Alteration of the fibrinolytic system is considered to be important in the development of deep venous thrombosis (DVT). Using specific assays for tissue plasminogen activator (t-PA) activity, t-PA inhibitor (PAI) and t-PA antigen, we measured these activities in 16 women who developed DVT during their pregnancies. A group of 24 healthy females of comparable age was studied as controls. PAI was increased in 87% of these patients compared to the healthy controls. In some of these patients a defect in release of t-PA from vascular endothelium was found as well. The site at which blood was sampled for analysis appeared to be an important criterion in the ex vivo assessment of functional t-PA reserve and PAI levels, though relatively less so for the latter measurement. The unaffected lower limbs, relative to the unaffected upper limbs, showed an increase in PAI and a demonstrable decrease in t-PA release, both representing increased risk factors for rethrombosis. The affected lower limbs showed similar but more accentuated changes in these parameters.

Staged distraction osteogenesis followed by arthrodesis using internal fixation as a form of surgical treatment for complex conditions of the ankle

Aims

The aim of this study was to describe the technique of distraction osteogenesis followed by arthrodesis using internal fixation to manage complex conditions of the ankle, and to present the results of this technique.

Patients and Methods

Between 2008 and 2014, distraction osteogenesis followed by arthrodesis using internal fixation was performed in 12 patients with complex conditions of the ankle due to trauma or infection. There were eight men and four women: their mean age was 35 years (23 to 51) at the time of surgery. Bone healing and functional recovery were evaluated according to the criteria described by Paley. Function was assessed using the ankle-hindfoot scale of the American Orthopedic Foot and Ankle Society (AOFAS).

Results

A solid fusion of the ankle and eradication of infection was achieved in all patients. A mean lengthening of 6.1 cm (2.5 to 14) was achieved at a mean follow-up of 25.2 months (14 to 37). The mean external fixation index (EFI) was 42 days/cm (33.3 to 58). The function was judged to be excellent in six patients and good in six patients. Bone results were graded as excellent in ten patients and good in two patients. The mean AOFAS score was 37.3 (5 to 77) preoperatively and 75.3 (61 to 82) at the final follow-up. Minor complications, which were treated conservatively, included pain, pin-tract infection, loosening of wires, and midfoot stiffness. Major complications, which were treated surgically included grade V pin-tract infection with inflammation and osteolysis, poor consolidation of the regenerate bone, and soft-tissue invagination. The reoperations required to treat the major complications included the exchange of pins and wires, bone grafting and invagination split surgery.

Conclusion

The technique of distraction osteogenesis followed by arthrodesis using internal fixation is an effective form of treatment for the management of complex conditions of the ankle. It offers a high rate of union, an opportunity to remove the frame early, and a reduced EFI without infection or wound dehiscence. Cite this article: Bone Joint J 2018;100-B:755–60.

[The experimental study on endoplasmic reticulum stress-participated outer hair cell apoptosis in cadherin 23 gene mutant mice]

Objective: To test the mechanism and upstream pathway of outer hair cell apoptosis in Cadherin 23 (Cdh23) gene mutant mice. Method: The mutant Cdh23(erl/erl)(erl) mice were collected as the study group, while the C57BL/6J (B6) mice were chosen as the control group. A total of 70 mice per group were used in this study. The study group and control group underwent auditory-evoked brainstem response (ABR) tests at the same age. The terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to detect outer hair cell(OHC) apoptosis. The qRT-PCR was conducted to test the expression of ER stress markers immunoglobulin-binding protein (BiP) and C/EBP homologous protein (CHOP) mRNA. The expression and location of BiP and CHOP protein in OHC were detected by immunostaining. The expression of BiP protein in cochleae was identified by Western blot. The expression and location of CDH23 protein in OHC were discovered by immunostaining. Results: The ABR thresholds in erl mice were significantly higher than those in B6 mice at the age of 1 and 3 months (both P<0.05). The surface preparation with TUNEL staining confirmed OHC apoptosis in erl mouse cochleae which showed a higher TUNEL positive cell ratio than B6 mouse(t=11.291, P<0.01). The ER stress marker Bip and Chop mRNA were upregulated in the erl mouse inner ear, when compared with those in the B6 mouse(both P<0.05). The BiP protein extracted from the erl mouse cochleae was significantly higher than that of B6 mouse measured by Western blot (t=3.66, P=0.02). Immunostaining showed that BiP and CHOP were highly detected in the OHC in erl mouse cochleae, and was mainly detected in the perinuclear region of OHC. However, a bare BiP and CHOP signal were shown in B6 mouse cochleae. The CDH23 protein was specifically localized at the top of the OHC in B6 mice, indicating the localization of the tip links in hair bundle stereocilia. On the contrary, the CDH23(erl) protein was found to be localized from the top to the nuclei of the OHC in erl mice. Portions of the CDH23(erl) proteins failed to reach the top of the hair bundles and remained in the OHC cytoplasm. Conclusion: As the downstream response of the Cdh23 gene mutation, portions of the mutant CDH23(erl) protein was accumulated in ER lumen resulting in the increase of ER loading and ultimately triggered ER stress and hair cell apoptosis in erl mouse cochleae.

Magnetically Coated Bioabsorbable Stents for Renormalization of Arterial Vessel Walls after Stent Implantation

The insertion of a stent in diseased arteries is a common endovascular procedure that can be compromised by the development of short- and long-term inflammatory responses leading to restenosis and thrombosis, respectively. While treatment with drugs, either systemic or localized, has decreased the incidence of restenosis and thrombosis these complications persist and are associated with a high mortality in those that present with stent thrombosis. We reasoned that if stents could be made to undergo accelerated endothelialization in the deployed region, then such an approach would further decrease the occurrence of stent thrombosis and restenosis thereby improving clinical outcomes. Toward that objective, the first step necessitated efficient capture of progenitor stem cells, which eventually would become the new endothelium. To achieve this objective, we engineered intrinsic ferromagnetism within nonmagnetizable, biodegradable magnesium (Mg) bare metal stents. Mg stents were coated with biodegradable polylactide (PLA) polymer embedding magnetizable iron-platinum (FePt) alloy nanoparticles, nanomagnetic particles, ⁿMags, which increased the surface area and hence magnetization of the stent. ⁿMags uniformly distributed on stents enabled capture, under flow, up to 50 mL/min, of systemically injected iron-oxide-labeled (IO-labeled) progenitor stem cells. Critical parameters enhancing capture efficiency were optimized, and we demonstrated the generality of the approach by showing that ⁿMag-coated stents can capture different cell types. Our work is a potential paradigm shift in engineering stents because implants are rendered as tissue in the body, and this "natural stealthiness" reduces or eliminates issues associated with pro-inflammatory immune responses postimplantation.

[Gasless endoscopic selective lateral neck dissection via an anterior chest approach for papillary thyroid carcinomas]

Objective: To assess the safety and curative effect of gasless endoscopic selective lateral neck dissection (GESLND) via an anterior chest approach for papillary thyroid carcinoma (PTC). Methods: Eighteen patients with PTC(T1-2N1bM0, size<3.0 cm), having GESLND via an anterior chest approach, were included from November 2008 to December 2016. Results: GESLND via an anterior chest approach was successfully performed in all 18 PTC patients (seven male and eleven female) with 83.3% of T1 and 16.7% of T2. The mean operative time of selective lateral neck dissection was 73 min (range 51-92 min). The mean of intraoperative bleeding was 61.1 ml (range 30-120 ml). No major complications occurred except one transient hypoparathyroidism. No residual thyroid glands were detected on ultrasonography and thyroglobulin was(0.73±0.16)ng/ml three months postoperatively. The median of follow-up was 54.5 months (range 6-104 months). No recurrence disease was observed in any patient on ultrasonography, computer tomography, thyroglobulin or selective iodine-131 scan during the follow-up period. The cosmetic result and functional preservation was excellent, when the assessments were performed three months postoperatively. Conclusion: GESLND via an anterior chest approach is feasible and safe for selected PTCs, with superior appearance.

[The significance of preservation of the supraclavicular nerve in endoscopic thyroidectomy via gasless anterior chest approach]

Objective: To evaluate the significance for the preservation of the supraclavicular nerve in endoscopic thyroidectomy via gasless anterior chest approach. Methods: We retrospectively evaluated 168 patients who underwent unilateral endoscopic thyroidectomy via gasless anterior chest approach, with preservation of the medial branch of the supraclavicular nerve in 110 patients and not in other 58 patients. Semmes-Weinstein monofilament (SWM) test and a visual analogue scale (VAS) were used to assess the recovery of sensation in anterior chest within 1-12 months postoperatively. Difference in the scores of SWM or VAS between groups was tested with Mann-Whitney U test, and the rates of SWM and VAS scores returning to normal levels in individual periods after surgery was compared with Chi-square test. Results: The preserved group showed more favorable results than the non-preserved group in both SMW and VAS scores. Compared to control group, SWM score in preserved group possessed a higher rate recovery to normal level at any period after operation, which was close to complete normality in 7-9 months postoperatively, and SWM score in non-preserved group was still partially normal in 10-12 months from surgery. Preferable results for VAS were also found in the preserved group, except no significant difference in VAS between groups in1-3 months or 10-12 months after operation. Conclusion: Preservation of the medial branch of the supraclavicular nerve in endoscopic thyroidectomy via gasless anterior chest approach can improve sensation recovery in anterior chest, thus improving postoperative quality of life of patients.