The Effect of Adding Modified Chitosan on the Strength Properties of Bacterial Cellulose for Clinical Applications

Currently, several materials for the closure of the dura mater (DM) defects are known. However, the long-term results of their usage reveal a number of disadvantages. The use of antibiotics and chitosan is one of the major trends in solving the problems associated with infectious after-operational complications. This work compares the mechanical properties of samples of bacterial nanocellulose (BNC) impregnated with Novochizol™ and vancomycin with native BNC and preserved and native human DM. An assessment of the possibility of controling the mechanical properties of these materials by changing their thickness has been performed by statistical analysis methods. A total of 80 specimens of comparable samples were investigated. During the analysis, the results obtained, the factor of Novochizol™ addition has provided a statistically significant impact on the strength properties (Fisher Criteria p-value 0.00509 for stress and 0.00112 for deformation). Moreover, a stronger relationship between the thickness of the samples and their ultimate load was shown: R2=0.236 for BNC + Novochizol™ + vancomycin, compared to R2=0.0405 for native BNC. Using factor analysis, it was possible to show a significant effect of modified chitosan (Novochizol™) on the ultimate stress (p-value = 0.005).

Oxytocin and Migraine Headache

This article reviews material presented at the 2016 Scottsdale Headache Symposium. This presentation provided scientific results and rationale for the use of intranasal oxytocin for the treatment of migraine headache. Results from preclinical experiments are reviewed, including in vitro experiments demonstrating that trigeminal ganglia neurons possess oxytocin receptors and are inhibited by oxytocin. Furthermore, most of these same neurons contain CGRP, the release of which is inhibited by oxytocin. Results are also presented which demonstrate that nasal oxytocin inhibits responses of trigeminal nucleus caudalis neurons to noxious stimulation using either noxious facial shock or nitroglycerin infusion. These studies led to testing the analgesic effect of intranasal oxytocin in episodic migraineurs-studies which did not meet their primary endpoint of pain relief at 2 h, but which were highly informative and led to additional rat studies wherein inflammation was found to dramatically upregulate the number of oxytocin receptors available on trigeminal neurons. This importance of inflammation was supported by a series of in vivo rat behavioral studies, which demonstrated a clear craniofacial analgesic effect when a pre-existing inflammatory injury was present. The significance of inflammation was further solidified by a small single-dose clinical study, which showed analgesic efficacy that was substantially stronger in chronic migraine patients that had not taken an anti-inflammatory drug within 24 h of oxytocin dosing. A follow-on open label study examining effects of one month of intranasal oxytocin dosing did show a reduction in pain, but a more impressive decrease in the frequency of headaches in both chronic and high frequency episodic migraineurs. This study led to a multicountry double blind, placebo controlled study studying whether, over 2 months of dosing, "as needed" dosing of intranasal oxytocin by chronic and high frequency migraineurs would reduce the frequency of their headaches compared to a 1-month baseline period. This study failed to meet its primary endpoint, due to an extraordinarily high placebo rate in the country of most of the patients (Chile), but was also highly informative, showing strong results in other countries and strong post hoc indications of efficacy. The results provide a strong argument for further development of intranasal oxytocin for migraine prophylaxis.

Headaches in brain tumor patients: primary or secondary?

BACKGROUND

Headaches occur commonly in all patients, including those who have brain tumors. It has been argued that there is a classic "brain tumor headache type" - defined by the International Headache Society as one that is localized, progressive, worse in the morning, aggravated by coughing or bending forward, develops in temporal and often spatial relation to the neoplasm, and resolves within 7 days of surgical removal or treatment with corticosteroids.

METHODS

Using the search terms "headache and brain tumors," "intracranial neoplasms and headache," and "facial pain and brain tumors," we reviewed the literature from the past 20 years on brain tumor-associated headache and reflected upon the International Classification of Headache Disorders-3 (ICHD-3). In a separate, complementary paper, the proposed mechanisms of brain tumor headache are reviewed.

RESULTS

We discuss multiple clinical presentations of brain tumor headaches, present the ICHD-3 diagnostic criteria for each type of headache, and then apply our findings to the ICHD-3. Our primary and major finding was that brain tumor headaches can present similarly to primary headaches in those with a predisposition to headaches, suggesting that following ICHD-3 criteria could cause a clinician to overlook a headache caused by a brain tumor. We further find that some types of headaches are not explicitly discussed in the ICHD-3 and also propose that the International Headache Society formally define SMART (Stroke-like Migraine Attacks after Radiation Therapy) syndrome given the increasing amount of literature on this disorder.

CONCLUSION

Our literature review revealed that brain tumor headache uncommonly presents with classic brain tumor headache characteristics and often satisfies criteria for a primary headache category such as migraine or tension-type. Thus, clinicians may miss headaches due to brain tumors in following ICHD-3 criteria, and the distinction between primary and secondary headache disorders may not be so clear-cut.

Ectopic ossification in the cranial dura mater in dialysis patients with secondary hyperparathyroidism

We report the case of a 69-year-old woman with secondary hyperparathyroidism who underwent maintenance haemodialysis therapy for 17 years and who presented with severe dural calcification and right subdural haematoma. Her dura mater displayed a rock barnacle-like appearance, and cerebral superficial arteries adhered to the sclerotic lesions. On the microscopic observation, calcified tissue with a clear lamellar structure and osteopontin immunoreactivity was observed. Tartrate-resistant acid phosphatase immunoreactive polynucleated giant cells infiltrated around the tissue. Such morphological properties are specific to the calcified tissue formed through a bone formation-like mechanism that is often observed in arterial media in patients with chronic kidney disease.