Editorial: Too many neurosurgeons

This report describes 2 cases of cerebral revascularization carried out using an autogenous venous graft instead of a superficial temporal artery because of insufficient diameter of the artery.     

Merkel cell carcinoma: Long term survival in a patient with proven brain metastasis and presumed choroid metastasis

Merkel cell carcinoma (Trabecular carcinoma) is a rare malignant tumor of the skin. Because these tumors tend to spread locally via the lymphatic system, very few papers have dealt with the treatment of distant metastasis. Systemic disease is uncommon and usually fatal.

In this paper, we report a case of Merkel cell carcinoma with proven brain metastasis and a solid choroidal tumor. The patient responded well to radiation and chemotherapy and is alive and neurologically intact three years after diagnosis. All previous patients with metastatic Merkel cell carcinoma to the brain died within two months of the diagnosis. We use this case to discuss possible routes of metastatic dissemination and to review the treatment options in patients with distant metastatic disease. To our knowledge, this is the first reported case of presumed choroidal metastasis of Merkel cell carcinoma and the longest documented survival in a patient with brain involvement.     

Altered lung function in rats after subacute exposure to n-butyl isocyanate

The objectives of this study were to use pulmonary function tests, blood gas measurements and bronchoalveolar lung lavage (BAL) to characterize lesions in the respiratory tract of young adult male Wistar rats as a result of a 5-day exposure (6 h/day) to 0, 1.1, 6.2, 15 or 26 mg n-butyl isocyanate (n-BIC)/m³ air. Further objectives were to probe the diagnostic sensitivities of these procedures in comparison with more traditional evaluations (clinical observation, lung weight, histopathology). Measurements were performed during post-exposure weeks 2 and 5. Most rats exposed to 26 mg/m³ died or were sacrificed in a moribund state during post-exposure week 2. All other rats survived the exposure regimen. In rats exposed to 15 and 26 mg/m³ a significant decrease in body weight, laboured breathing, hypoactivity, nasal discharge, cyanosis, and hypothermia were observed. Pulmonary function measurements revealed increased total lung capacity (TLC) and residual volume (RV), decreased forced expiratory flow rates and quasistatic compliance in rats exposed to 26 mg/m³. At the end of the observation period rats exposed to 6.2 and 15 mg/m³ air were hyperresponsive to an acetylcholine bronchoprovocation aerosol. Arterial blood gas measurements revealed an arterial hypoxia and an increase in venous admixture, suggesting a severe mismatch of the ventilation-perfusion relationship, Biochemical and cellular components in BAL fluid (BALF) indicated a concentration dependent and protracted increase of polymorphonuclear leucocytes and further inflammatory parameters. In the 1.1 mg/m³ group BALF parameters were not significantly elevated. The major histopathological lesions of the lung were thickening of septa, emphysema, and intra-alveolar oedema in rats exposed to 26 mg/m³. Collectively, these results demonstrate obstructive and progressive lung disease with associated gas trapping and severe disturbance of the ventilation perfusion relationship which is considered to be the cause of delayed mortality. In terms of variability and sensitivity the increase in BALF parameters was most sensitive in indicating the diseased state of the lung.     

Acute toxicity of bicyclic phosphorus esters

The acute toxicity of 4-ethyl-1-phospha-2,6,7-trioxabicyclo (2.2.2) octane-1-oxide and 4-ethyl-1-phospha-2,6,7-trioxabicyclo (2.2.2) octane has been determined by different routes of application in various species of animals. The compounds stimulate the activity of the central nervous system and are highly toxic. They showed no toxic cumulative effects. The presence of the bicyclic phosphate ester in the combustion products of specific rigid polyurethane foams is dicussed. The question is raised whether there may be an additional hazard caused by this combustion product in a real fire situation.     

The effect of oxidation on the degradation of photocrosslinkable alginate hydrogels

Recently, we reported on a new photocrosslinkable alginate-based hydrogel, which has controllable physical and cell adhesive properties. The macromer solution containing cells can be injected in a minimally invasive manner into a defect site and crosslinked while maintaining high cell viability. The number of hydrolyzable ester bonds in the formed crosslinks may be controlled by altering the degree of methacrylation on the alginate polymer backbone. However, the degradation rate of the hydrogels has been found to be slower in vivo than in vitro. The purpose of this study was to develop photocrosslinked alginate hydrogels with an increased range of biodegradation rates for more rapid in vivo biodegradation in regenerative medicine and bioactive factor delivery applications. Therefore, we oxidized alginate prior to methacrylation to change the uronate residue conformations to an open-chain adduct, which makes it more vulnerable to hydrolysis. Here, we demonstrate that the swelling behavior, degradation profiles, and storage moduli of photocrosslinked hydrogels formed from oxidized, methacrylated alginates (OMAs) are tunable by varying the degree of alginate oxidation. The OMA macromers and photocrosslinked OMA hydrogels exhibited cytocompatibility when cultured with human bone marrow-derived mesenchymal stem cells (hBMMSCs). In addition, hMSCs derived from bone marrow or adipose tissue photoencapsulated within these hydrogels remained viable, and their proliferation rate was a function of alginate oxidation level and initial hydrogel weight fraction. Oxidation permits a wider range of photocrosslinked OMA hydrogels physical properties, which may enhance these therapeutic materials' utility in tissue engineering and other biomedical applications.