Melatonin Improves Vasogenic Edema via Inhibition to Water Channel Aquaporin-4 (AQP4) and Metalloproteinase-9 (MMP-9) Following Permanent Focal Cerebral Ischemia.

Background: The efficacy of melatonin in reducing vasogenic and cytotoxic edema was investigated using a model of permanent middle cerebral artery occlusion (pMCAO). Methods: Rats underwent pMCAO, followed by intravenous administration of either melatonin (5 mg/kg) or a vehicle 10 min post-insult. Brain infarction and edema were assessed, and Western blot analyses were conducted to examine the expression levels of aquaporin-4 (AQP4), metalloproteinase-9 (MMP-9), and the neurovascular tight-junction protein ZO-1 upon sacrifice. The permeability of the blood-brain barrier (BBB) was measured using spectrophotometric quantification of Evans blue dye leakage. Results: Compared to controls, melatonin-treated rats exhibited a significant reduction in infarct volume by 26.9% and showed improved neurobehavioral outcomes (p < 0.05 for both). Melatonin treatment also led to decreased Evans blue dye extravasation and brain edema (p < 0.05 for both), along with lower expression levels of AQP4 and MMP-9 proteins and better preservation of ZO-1 protein (p < 0.05 for all). Conclusions: Therefore, melatonin offers neuroprotection against brain swelling induced by ischemia, possibly through its modulation of AQP4 and MMP-9 activities in glial cells and the extracellular matrix (ECM) during the early phase of ischemic injury.

Viscolin-mediated antiapoptotic and neuroprotective effects in cortical neurons exposed to oxygen-glucose deprivation and rats subjected to transient focal cerebral ischemia.

OBJECTIVE: Previously, we have successfully purified and synthesized viscolin, an agent derived from Viscum coloratum extract, which has shown significant potential in the treatment of stroke. Our study aimed to evaluate the neuroprotective effects of viscolin. METHODS: We first assessed the cytotoxicity of viscolin on primary neuronal cultures and determined its antioxidant and radical scavenging properties. Subsequently, we identified the optimal dose-response of viscolin in protecting against glutamate-induced neurotoxicity. RESULTS: Our results demonstrated that viscolin at a concentration of 10 µM effectively reduced neuronal cell death up to 6 hours after glutamate-induced neurotoxicity. Additionally, we investigated the therapeutic window of opportunity and the potential of viscolin in preventing necrotic and apoptotic damage in cultured neurons exposed to oxygen glucose deprivation-induced neurotoxicity. Our findings showed that viscolin treatment significantly reduced DNA breakage, prevented the release of cytochrome c from mitochondria to cytosol, increased the expression of anti-apoptotic protein Bcl-2, decreased the expression of pro-apoptotic protein Bax, and reduced the number of TUNEL-positive cells. Additionally, our in vivo investigation demonstrated a reduction in brain infarction following middle cerebral artery occlusion. CONCLUSION: Viscolin has potential utility as a therapeutic agent in the treatment of stroke.

Erector Spinae Plane Block Versus Thoracolumbar Interfascial Plane Block in Lumbar Spine Surgery: A Meta-Analysis of Randomized Controlled Trials.

STUDY DESIGN: Meta-analysis. OBJECTIVE: To compare the effectiveness of postoperative pain control between erector spinae plane block (ESPB) and thoracolumbar interfascial plane (TLIP) block in lumbar spine surgery. METHODS: PubMed, Embase, and MEDLINE electronic databases were searched for articles containing randomized controlled trials (RCTs) published between January 1900 and January 2024. We extracted the postoperative mean pain score, the first 24-h postoperative morphine consumption, and their standard deviation from the included studies. Meta-analysis was performed using the functions available in the metafor package in R software. We pooled continuous variables using an inverse variance method with a random-effects model and summarized them as standardized mean differences. RESULTS: Five RCTs that directly compared the ESPB and TLIP block in lumbar spine surgery were included, enrolling 432 participants randomly into the two groups with 216 participants in each group. The pooled analyses showed that there was no significant difference between the ESPB and TLIP groups in terms of lower pain scores during the early (1 h) (standardized mean difference [SMD] -1.49, 95% confidence interval [CI], -3.10; 0.11), middle (12 h) (SMD -3.12, 95% CI, -6.86; 0.61), and late (24 h) (SMD -1.38, 95% CI, -3.01; 0.24) postoperative periods. There was also no significant difference in the first 24-h postoperative morphine equivalent consumption between the ESPB and TLIP groups (SMD -0.46 mg, 95% CI -1.23; 0.31). CONCLUSION: No significant difference was observed between the ESPB and TLIP block in terms of postoperative pain control and 24-h morphine equivalent consumption for lumbar spine surgery.

Anti-oxidative and anti-inflammatory effects of Ginkgo biloba extract (EGb761) on hindlimb skeletal muscle ischemia-reperfusion injury in rats.

In posterior spine surgery, retractors exert pressure on paraspinal muscles, elevating intramuscular pressure and compromising blood flow, potentially causing muscle injury during ischemia-reperfusion. Ginkgo biloba extract (EGb 761), known for its antioxidant and free radical scavenging properties and its role in treating cerebrovascular diseases, is investigated for its protective effects against muscle ischemia-reperfusion injury in vitro and in vivo. Animals were randomly divided into the control group, receiving normal saline, and experimental groups, receiving varying doses of EGb761 (25/50/100/200 mg/kg). A 2-h hind limb tourniquet-induced ischemia was followed by reperfusion. Blood samples collected pre-ischemia and 24 h post-reperfusion, along with muscle tissue samples after 24 h, demonstrated that EGb761 at 1000 µg/mL effectively inhibited IL-6 and TNF-α secretion in RAW 264.7 cells without cytotoxicity. EGb761 significantly reduced nitric oxide (NO) and malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, and increased glutathione (GSH) levels compared to the control after 24 h. Muscle tissue sections revealed more severe damage in the control group, indicating EGb761's potential in mitigating inflammatory responses and oxidative stress during ischemia-reperfusion injury, effectively protecting against muscle damage.

Surgical excision and radiotherapy for brain metastasis from colorectal cancer: How frailty and comorbidity indices influence outcome.

The incidence of brain metastasis (BM) from colorectal cancer (CRC) is increasing. This study aims to identify the clinical prognosticators and evaluate the prognostic validity of common comorbidity indices in patients with BM from CRC. This retrospective single-center study analyzed 93 patients with BM from CRC who received surgical excision and/or radiotherapy. The clinical characteristics and prognostic indices including the 5-item modified frailty index (mFI-5) and prognostic nutritional index (PNI) were calculated from the collected patient data and analyzed. In this study, 66 (71.0%), 10 (10.8%), and 17 (18.3%) patients received whole-brain radiotherapy (WBRT) alone, surgery alone, and surgery plus WBRT, respectively. The median survival of all patients was 3.98 months (IQR: 1.74-7.99). The 2- and 3-year survival rates were 7.4% and 3.7%, respectively. Controlled primary tumor (p = 0.048), solitary BM (p = 0.001), surgery + radiation (p < 0.001), and greater PNI (p = 0.001) were independent predictors of favorable survival. In surgically treated patients, uncontrolled primary tumor (p = 0.006), presence of multiple BM (p < 0.001), and MFI-5 ≥ 2 (p = 0.038) were independent prognosticators. For patients who received WBRT, the presence of two (p = 0.004) or multiple (p < 0.001) BM and PNI (p < 0.001) were independent survival predictors MFI-5, multiple BM, and the status of the primary tumor were independent prognosticators for patients who underwent surgery for CRCBM. For patients who received WBRT, the PNI and the number of BM were independent survival predictors.

Risk Factors for Postoperative Ileus Following Spine Surgery: A Systematic Review With Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: Postoperative ileus (POI) can negatively impact patient recovery and surgical outcomes after spine surgery. Emerging studies have focused on the risk factors for POI after spine surgery. This study aimed to review the available literature on risk factors associated with POI following elective spine surgery. METHODS: Electronic databases were searched to identify relevant studies. Meta-analysis was performed using random-effect model. Risk factors for POI were summarized using pooled odds ratio (OR) with 95% confidence intervals (CI). RESULTS: Twelve studies were included in the present review. Meta-analysis demonstrated males exhibited a higher risk of POI than females odds ratio (OR, 1.76; 95% CI, 1.54-2.01). Patients with anemia had a higher risk of POI than those without anemia (OR, 1.48; 95% CI, 1.04-2.11). Patients with liver disease (OR, 3.3; 95% CI, 1.2-9.08) had a higher risk of POI. The presence of perioperative fluid and electrolyte imbalances was a predictor of POI (OR, 3.24; 95% CI, 2.62-4.02). Spine surgery involving more than 3 levels had a higher risk of POI compared to that with 1-2 levels (OR, 1.82; 95% CI, 1.03-3.23). CONCLUSIONS: Male sex and the presence of anemia and liver disease were significant patient factors associated with POI. Perioperative fluid and electrolyte imbalance and multilevel spine surgery significantly increased the risk of POI. In addition, through this comprehensive review, we identified several perioperative risk factors associated with the development of POI after spine surgery.

Outcomes of surgery and subsequent therapy for central nervous system oligoprogression in EGFR-mutated NSCLC patients.

BACKGROUND: Oligoprogression is an emerging issue in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC). However, the surgical treatment for central nervous system (CNS) oligoprogression is not widely discussed. We investigated the outcomes of craniotomy with adjuvant whole-brain radiotherapy (WBRT) and subsequent therapies for CNS oligoprogression in patients with EGFR-mutated NSCLC. METHODS: NSCLC patients with CNS oligoprogression were identified from a tertiary medical center. The outcomes of surgery with adjuvant WBRT or WBRT alone were analyzed, along with other variables. Overall survival and progression-free survival were analyzed using the log-rank test as the primary and secondary endpoints. A COX regression model was used to identify the possible prognostic factors. RESULTS: Thirty-seven patients with CNS oligoprogression who underwent surgery or WBRT were included in the study after reviewing 728 patients. Twenty-one patients underwent surgery with adjuvant WBRT, and 16 received WBRT alone. The median overall survival for surgery and WBRT alone groups was 43 (95% CI 17-69) and 22 (95% CI 15-29) months, respectively. Female sex was a positive prognostic factor for overall survival (OR 0.19, 95% CI 0.06-0.57). Patients who continued previous tyrosine kinase inhibitors (OR 3.48, 95% CI 1.06-11.4) and induced oligoprogression (OR 3.35, 95% CI 1.18-9.52) were associated with worse overall survival. Smoking history (OR 4.27, 95% CI 1.54-11.8) and induced oligoprogression (OR 5.53, 95% CI 2.1-14.7) were associated with worse progression-free survival. CONCLUSIONS: Surgery combined with adjuvant WBRT is a feasible treatment modality for CNS oligoprogression in patients with EGFR-mutated NSCLC. Changing the systemic-targeted therapy after local treatments may be associated with improved overall survival.

Is there a weekend effect in spine surgery?: A systematic review and meta-analysis of postoperative outcomes.

BACKGROUND: The concept of a weekend effect is that patients admitted to hospitals on the weekend tend to have poorer outcomes compared to those admitted on a weekday. Whether there is a weekend effect among patients receiving spine surgery is not well described in the literature. We sought to perform a systematic review with meta-analysis to explore whether a weekend effect exists among patients experiencing spinal surgery. METHODS: The Cochrane Library, PubMed, Embase, and MEDLINE electronic databases were searched for relevant articles. Meta-analyses were performed using functions available in the metafor package within the R software. We obtained adjusted odds ratios (OR) from included studies and pooled OR through an inverse variance method. A random-effects model was applied for meta-analysis and effect sizes were presented with their corresponding 95% confidence intervals (CI). RESULTS: Our search strategy identified 316 references from electronic databases and eventually 6 studies were included in the analysis. The pooled result of 5 studies reporting overall complication rate indicated significant increased risk of complications among the weekend admission group (OR, 1.35; 95% CI, 1.01 to 1.80). The pooled results of 3 studies demonstrated no difference in overall mortality rates between these 2 groups of patients (OR, 1.18; 95% CI, 0.67 to 1.97). CONCLUSIONS: In spinal surgical patients, the weekend effect significantly contributes to a higher complication rate. Knowledge of potential adverse events in patients admitted on weekends is necessary for spinal surgeons and caregivers to improve patient outcomes with spinal surgery.

Quantification of vessel separation using the carotid-jugular angle to predict the nerve origin of neck peripheral nerve sheath tumours: a pooled analysis of cases from the literature and a single-center cohort.

BACKGROUND: Postoperative nerve palsy is a major complication following resection of neck peripheral nerve sheath tumours (PNSTs). Accurate preoperative identification of the nerve origin (NO) can improve surgical outcomes and patient counselling. MATERIAL AND METHODS: This study was a retrospective cohort and quantitative analysis of the literature. The authors introduced a parameter, the carotid-jugular angle (CJA), to differentiate the NO. A literature review of neck PNST cases from 2010 to 2022 was conducted. The CJA was measured from eligible imaging data, and quantitative analysis was performed to evaluate the ability of the CJA to predict the NO. External validation was performed using a single-centre cohort from 2008 to 2021. RESULTS: In total, 17 patients from our single-centre cohort and 88 patients from the literature were analyzed. Among them, 53, 45, and 7 patients had sympathetic, vagus, and cervical nerve PNSTs, respectively. Vagus nerve tumours had the largest CJA, followed by sympathetic tumours, whereas cervical nerve tumours had the smallest CJA ( P <0.001). Multivariate logistic regression identified a larger CJA as a predictor of vagus NO ( P <0.001), and receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.907 (0.831-0.951) for the CJA to predict vagus NO ( P <0.001). External validation showed an AUC of 0.928 (0.727-0.988) ( P <0.001). Compared with the AUC of the previously proposed qualitative method (AUC=0.764, 0.673-0.839), that of the CJA was greater ( P =0.011). The cut-off value identified to predict vagus NO was greater than or equal to 100°. Receiver operating characteristic analysis showed an AUC of 0.909 (0.837-0.956) for the CJA to predict cervical NO ( P <0.001), with a cut-off value less than 38.5°. CONCLUSIONS: A CJA greater than or equal to 100° predicted a vagus NO and a CJA less than 100° predicted a non-vagus NO. Moreover, a CJA less than 38.5 was associated with an increased likelihood of cervical NO.

Evaluation of the safety, radiographic and resident training results of thoracic pedicle screws placement using resection of the transverse process.

OBJECTIVE: This study aimed at the evaluation and assessment of a simple method, the transverse process resection (TPR) technique, for freehand thoracic pedicle screw placement and the learning curve for trainee surgeons. METHODS: In the TPR technique, the tip of the thoracic transverse process (TP) is removed to create an entry point in the cancellous bone of the TP, and the thoracic pedicle is cannulated from the TP. We retrospectively evaluated the safety and radiographic results of the TPR technique and compared with that of conventional pedicle screws. The training performance of seven neurosurgical residents with TPR techniques were evaluated. RESULTS: Among 46 patients, a total of 322 thoracic screws were analyzed, including 178 screws placed using the TPR technique and 144 screws using the conventional straight-forward (SF) technique. TPR screws had greater medial angulations in all levels from T2 to T12 compared to SF screws (p < 0.001). The incidence of pedicle breach was lower in the TPR screws compared to SF screws (6.2% vs. 21.5%, p < 0.001), especially for screws placed by residents (6.7% vs. 29.6%, p < 0.001). Residents had improved performance following a cadaveric training course on the TPR technique (p = 0.001). CONCLUSION: This study demonstrated the safety of the TPR technique for thoracic pedicle screw placement and its short learning curve for trainee surgeons.

Pathogenic variants in the SPTLC1 gene cause hyperkeratosis lenticularis perstans.

BACKGROUND: Hyperkeratosis lenticularis perstans (HLP), also known as Flegel disease, is a rare skin disease presenting with asymptomatic small hyperkeratotic papules. The lesions often appear on the dorsal feet and lower legs, and typically develop after the fourth decade of life. A genetic basis for HLP is suspected; however, so far no gene defect linked to the development of HLP has been identified. OBJECTIVES: We aimed to identify the genetic cause of HLP. METHODS: For mutational analysis we studied a cohort of five patients with HLP using next-generation sequencing (NGS). We used DNA -extracted from fresh skin biopsies alongside ethylenediamine tetraacetic acid (EDTA) blood samples from two patients, and formalin-fixed -paraffin-embedded skin biopsy material from three patients. In addition, immunofluorescence staining of HLP lesions from four patients was investigated. RESULTS: In all samples from the five patients with HLP we identified by NGS rare variants in the SPTLC1 gene. In four patients we detected small deletions/frameshift variants and in one patient a splicing variant, predicted to disturb the splicing process. In blood samples the detected variants were heterozygous with an allele frequency of 49% and 50%, respectively. In skin biopsies the allele frequency was within the range of 46-62%. Immunofluorescence staining revealed reduced SPTLC1 protein levels in skin of patients. CONCLUSIONS: Our findings suggest that pathogenic variants in the SPTLC1 gene are the underlying genetic cause of HLP. Of note, the identified variants were either frameshift- or splicing variants probably leading to nonsense-mediated mRNA decay and thus reduced SPTLC1 protein levels. We conclude that diminished SPTLC1, the key enzyme in sphingolipid biosynthesis, leads to the development of HLP, which highlights the sphingolipid pathway as a new therapeutic target.

Spinal giant cell-rich osteosarcoma-diagnostic dilemma and treatment strategy: A case report.

BACKGROUND: Giant cell-rich osteosarcoma (GCRO) is a rare histological variant of osteosarcoma. Spinal GCROs are extremely rare, with challenging diagnosis and management. Herein, we present a case of spinal GCRO at T2, which was not diagnosed in initial biopsy but after T2 corpectomy. We detailed the clinical course, management strategy, and outcome after a 4-year follow-up. CASE SUMMARY: A 17-year-old female patient presented with back pain followed by ascending paresthesia. Spinal computed tomography (CT) and magnetic resonance imaging (MRI) revealed a collapsed T2 vertebra with an enhancing osteolytic mass. CT-guided biopsy showed inconclusive morphology. Pathology from T2 corpectomy revealed GCRO. The patient subsequently received neoadjuvant chemotherapy followed by salvage operation of T2 costotransversectomy with grossly-total resection adjuvant chemoradiation. Upon treatment completion, she had complete GCRO remission. The 4-year follow-up spinal MRI showed no tumor recurrence. CONCLUSION: Spinal GCRO poses unique challenges in obtaining sufficient tissue diagnosis and complete surgical removal. However, long-term local control of spinal GCRO is possible following complete resection and adjuvant chemoradiation.

Safety and Efficacy of Sorafenib and Lenvatinib in Patients Who Underwent Surgery or Whole-Brain Radiotherapy for Brain Metastasis of Hepatocellular Carcinoma.

Surgery or whole-brain radiotherapy (WBRT) for the management of brain metastasis of hepatocellular carcinoma (HCC) is associated with improved survival. However, the efficacy of multi-tyrosine kinase inhibitors (TKIs) and possible bleeding complications have not been studied in these patients. Therefore, this study aimed at investigating TKI safety and efficacy in these patients. We retrospectively reviewed 39 patients who underwent surgery or WBRT for brain metastasis of HCC. Intracranial tumor bleeding rates were compared between patients who did and did not receive TKIs. Survival outcomes were analyzed using the log-rank and Cox regression tests. A total of 22 and 7 patients received sorafenib and lenvatinib, respectively. The intracranial tumor bleeding rates were 61.5% and 70% in patients who did and did not receive TKIs, respectively (p > 0.99). Survival analysis revealed craniotomy (adjusted odds ratio [AOR]: 0.45, p = 0.04), a higher Karnofsky Performance Score (AOR: 0.97, p < 0.01), and TKI use (AOR: 0.26, p < 0.01) were positive prognostic factors for overall survival. TKIs were associated with better survival outcomes in patients who underwent surgery or WBRT for brain metastasis of HCC and did not increase intracranial bleeding. Therefore, TKIs are efficacious and safe for treating brain metastasis of HCC.

Rabies Virus Glycoprotein-Mediated Transportation and T Cell Infiltration to Brain Tumor by Magnetoelectric Gold Yarnballs.

T lymphocyte infiltration with immunotherapy potentially suppresses most devastating brain tumors. However, local immune privilege and tumor heterogeneity usually limit the penetration of immune cells and therapeutic agents into brain tumors, leading to tumor recurrence after treatment. Here, a rabies virus glycoprotein (RVG)-camouflaged gold yarnball (RVG@GY) that can boost the targeting efficiency at a brain tumor via dual hierarchy- and RVG-mediated spinal cord transportation, facilitating the decrease of tumor heterogeneity for T cell infiltration, is developed. Upon magnetoelectric irradiation, the electron current generated on the GYs activates the electrolytic penetration of palbociclib-loaded dendrimer (Den[Pb]) deep into tumors. In addition, the high-density GYs at brain tumors also induces the disruption of cell-cell interactions and T cell infiltration. The integration of the electrolytic effects and T cell infiltration promoted by drug-loaded RVG@GYs deep in the brain tumor elicits sufficient T cell numbers and effectively prolongs the survival rate of mice with orthotopic brain tumors.

Technical Case Report of a Cranioplasty With ex vivo Frozen Ostoblastic Bone Graft From Large Skull Metastasis.

Objective: Liquid nitrogen cryotherapy has shown efficacy in the treatment of bone tumors of the extremities with good oncologic and functional outcomes. However, its application in metastatic skull tumors has been rarely reported and whether the adjuvant radiotherapy affects the future bone healing is not yet explored. We report an immediate cranioplasty with the resected osteoblastic bone, which underwent ex vivo cryotherapy, and discuss the surgical techniques and postoperative images. Methods: A 58-year-old man with esophageal adenocarcinoma, undergoing chemoradiotherapy, presented with a rapidly enlarging scalp mass for 5 months. Imaging revealed an enhancing mass, centered in the frontal skull bone with extracranial and intracranial invasion, suggestive of osteoblastic metastasis. After preoperative transarterial embolization, the tumor was excised en bloc. Immediate cranioplasty was performed with the osteoblastic bone graft after ex vivo cryotherapy. It was soaked in liquid nitrogen for 20 min, thawed at room temperature for 15 min, and soaked in povidone-iodine solution for 10 min. Then, the bone graft was fixed to its original place. Pathologic examination revealed metastasis originating from the esophagus. He underwent adjuvant radiotherapy for local tumor control. Results: He had an uneventful clinical course without any neurologic deficit. Brain imaging during the six-month follow-up showed no tumor recurrence and partial bony union. Conclusions: Cranioplasty using an autologous bone graft with ex vivo cryotherapy was helpful in the reconstruction of osteoblastic metastatic skull tumor treatment. It was a simple and cost-effective procedure that achieved satisfactory cosmetic results without negatively impacting bone healing, even after adjuvant radiotherapy.

Computer-Aided Three-Dimensional Virtual Surgical Planning in Complex Skull Base Reconstruction for Sphenoid Wing Dysplasia in Neurofibromatosis Type 1.

ABSTRACT: Unilateral sphenoid dysplasia is a rare but distinctive manifestation of neurofibromatosis type 1, causing pulsatile exophthalmos, decreased vision, and facial deformity. Surgical intervention is required to prevent visual deterioration. However, the reconstruction of a complex cranial base defect while fulfilling cosmetic needs is challenging. The asymmetric anatomy impedes identification and preservation of vital structures, and the use of bone grafts is often unsustainable due to resorption. Here we demonstrate a multimodal technique combining mirror-image-based virtual surgical planning, stereolithography, and neuronavigation to achieve skull base reconstruction and restore facial symmetry in an neurofibromatosis type 1 patient with sphenoid dysplasia. Preoperative surgical planning involved mirror-image simulation based on the unaffected contralateral counterpart and a stereolithographic skull-base model fabricated to design a patient-specific titanium mesh. Surgical reconstruction via the transcranial approach under intraoperative neuronavigation was performed. Immediate resolution of pulsatile proptosis was observed postoperatively. With the help of virtual surgical planning, stereolithography, and neuronavigation, precise and sustainable reconstruction with patient-specific implants can be tailored for a complex skull base defect.

Bioengineering of a Full-Thickness Skin Equivalent in a 96-Well Insert Format for Substance Permeation Studies and Organ-On-A-Chip Applications.

The human skin is involved in protecting the inner body from constant exposure to outer environmental stimuli. There is an evident need to screen for toxicity and the efficacy of drugs and cosmetics applied to the skin. To date, animal studies are still the standard method for substance testing, although they are currently controversially discussed Therefore, the multi-organ chip is an attractive alternative to replace animal testing. The two-organ chip is designed to hold 96-well cell culture inserts (CCIs). Small-sized skin equivalents are needed for this. In this study, full-thickness skin equivalents (ftSEs) were generated successfully inside 96-well CCIs. These skin equivalents developed with in vivo-like histological architecture, with normal differentiation marker expressions and proliferation rates. The 96-well CCI-based ftSEs were successfully integrated into the two-organ chip. The permeation of fluorescein sodium salt through the ftSEs was monitored during the culture. The results show a decreasing value for the permeation over time, which seems a promising method to track the development of the ftSEs. Additionally, the permeation was implemented in a computational fluid dynamics simulation, as a tool to predict results in long-term experiments. The advantage of these ftSEs is the reduced need for cells and substances, which makes them more suitable for high throughput assays.

A Method for Determination and Simulation of Permeability and Diffusion in a 3D Tissue Model in a Membrane Insert System for Multi-well Plates.

In vitro cultivated skin models have become increasingly relevant for pharmaceutical and cosmetic applications, and are also used in drug development as well as substance testing. These models are mostly cultivated in membrane-insert systems, their permeability toward different substances being an essential factor. Typically, applied methods for determination of these parameters usually require large sample sizes (e.g., Franz diffusion cell) or laborious equipment (e.g., fluorescence recovery after photobleaching (FRAP)). This study presents a method for determining permeability coefficients directly in membrane-insert systems with diameter sizes of 4.26 mm and 12.2 mm (cultivation area). The method was validated with agarose and collagen gels as well as a collagen cell model representing skin models. The permeation processes of substances with different molecular sizes and permeation through different cell models (consisting of collagen gel, fibroblast, and HaCaT) were accurately described. Moreover, to support the above experimental method, a simulation was established. The simulation fits the experimental data well for substances with small molecular size, up to 14 x 10-10 m Stokes radius (4,000 MW), and is therefore a promising tool to describe the system. Furthermore, the simulation can considerably reduce experimental efforts and is robust enough to be extended or adapted to more complex setups.

Dynamic contrast-enhanced MRI in advanced nonsmall-cell lung cancer patients treated with first-line bevacizumab, gemcitabine, and cisplatin.

PURPOSE: To investigate dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of advanced nonsmall-cell lung cancer (NSCLC) patients treated with the antiangiogenic agent bevacizumab combined with gemcitabine and cisplatin as first-line treatment. MATERIALS AND METHODS: All patients were enrolled for MRI and computed tomography (CT) before and after the first three courses of bevacizumab combination chemotherapy. Pharmacokinetic parameters (K(trans), k(ep), v(e), v(p)) derived from DCE MRI were computed for the main mass. Parametric histogram analysis was obtained to evaluate changes of the internal tumor composition and for correlation with tumor response measured on CT. RESULTS: After three cycles of treatment, 11 patients showed decreased tumor size and a decreased value of all MR-derived pharmacokinetic parameters. Among these parameters, there was a significant decrease of mean and standard deviation of the K(trans) histogram as well as a decrease of mean of the k(ep) histogram (P < 0.05). Tumors with larger mean values of rate constant k(ep) (P < 0.0001) and smaller standard deviation of volume of extravascular extracellular space fraction v(e) (P < 0.0001) on histograms before chemotherapy were considered predictors for treatment response. CONCLUSION: DCE MRI enables a functional analysis of the treatment response of NSCLC. MRI parametric histogram has the potential to predict early treatment response of combined bevacizumab, gemcitabine, and cisplatin.