Influence of surface pretreatment of titanium- and cobalt-based biomaterials on covalent immobilization of fibrillar collagen

Collagen type-I is a major component of the extracellular matrix of most tissues and it is increasingly utilized for surface engineering of biomaterials to accelerate receptor-mediated cell adhesion. In the present study, coatings with layers of fibrillar type-I collagen were prepared on titanium, titanium alloy, and cobalt alloy to improve initial osteoblast adhesion and implant-tissue integration. To suppress the quick in vivo degradation rate of collagen the deposited layers were covalently immobilized at the metal surfaces as well as chemically cross-linked. The application of different oxidation techniques to the metallic substrates resulted in surfaces with varying hydroxyl group contents, which directly influenced the amount of immobilized silane coupling agents. It was found that a high density of surface-bound coupling agents increased the stability of the covalently linked collagen layers. After coating of metallic biomaterials with a cross-linked collagen layer, an improved cellular response of human osteoblast-like cells (MG-63) in vitro could be recognized.     

Patterns of protein expression in infectious meningitis: a cerebrospinal fluid protein array analysis

Seventy-nine cytokines, chemokines, and growth factors were measured by protein array analysis in the cerebrospinal fluid of patients with meningitis and controls. Several factors were found to be regulated, which have not been studied in the CNS before, e.g., macrophage inflammatory protein-1delta (CCL15) and neutrophil-activating peptide-2 (CXCL7). In pneumococcal meningitis, other new observations were an increase of macrophage migration inhibitory factor, monocyte chemoattractant protein-2 (CCL8), pulmonary and activation-regulated chemokine (CCL18), and macrophage inflammatory protein-3alpha (CCL20), and a sustained upregulation of several growth factors. In viral meningitis, new findings were an elevation of CCL8, thrombopoietin, and vascular endothelial growth factor.     

Do female sex steroids adversely or beneficially affect the depressed immune responses in males after trauma-hemorrhage?

HYPOTHESIS: Administration of female sex steroids in males after trauma-hemorrhage has salutary effects on the depressed immune responses. DESIGN: Randomized laboratory experiment. INTERVENTIONS: Male C3H/HeN mice were subjected to midline laparotomy and hemorrhagic shock (35+/-5 mm Hg for 90 minutes, then resuscitation) or sham operation and received subcutaneous 17beta-estradiol (40 microg/kg body weight) or corn oil vehicle at the beginning of resuscitation. MAIN OUTCOME MEASURES: At 24 hours after hemorrhage, the animals were killed and plasma 17beta-estradiol and IL-6, splenocyte interleukin (IL) 2, IL-3, and IL-10 production as well as splenic and peritoneal macrophage IL-1beta, IL-10, and IL-6 release were measured. RESULTS: Splenocyte IL-2 and IL-3 release were significantly depressed after hemorrhage in vehicle-treated mice (P<.05, analysis of variance). Treatment with 17beta-estradiol after hemorrhage led to the restoration of splenocyte IL-2 and IL-3 release. The depressed proinflammatory cytokine (IL-1 and IL-6) release seen in splenic and peritoneal macrophages was restored in the 17beta-estradiol-treated hemorrhage group. In contrast, the sustained release of the anti-inflammatory cytokine IL-10 by splenocytes and splenic and peritoneal macrophages in vehicle-treated mice after hemorrhage was decreased in 17beta-estradiol-treated mice. The increase in circulating IL-6 levels after hemorrhage was significantly attenuated in 17beta-estradiol-treated mice. Although administration of 17beta-estradiol increased plasma 17beta-estradiol levels by approximately 100% in sham as well as hemorrhage groups, improved immune responses were seen only in posthemorrhage 17beta-estradiol-treated mice. There was no adverse effect of 17beta-estradiol treatment in the sham or posthemorrhage groups. CONCLUSION: Since administration of a single dose of 17beta-estradiol in males after trauma-hemorrhage restores the immune functions and decreases circulating levels of IL-6, hormones with estrogenic properties should be considered as safe and novel therapeutic agents for restoring the immune responsiveness in male trauma victims.     

Variation in radiation-induced apoptosis in ataxia telangiectasia lymphoblastoid cell lines

Purpose : To investigate and compare the ability of Epstein-Barr virus-transformed lymphoblastoid cell lines (LCL) from healthy individuals (normals) and ataxia telangiectasia (A-T) patients to undergo apoptosis after exposure to ionizing radiation. Materials and methods : Four normal and eight A-T LCL were exposed to doses of up to 20 Gy ionizing radiation. Apoptosis induction was studied 24 h after irradiation using three different methods: measurement of caspase-3 activity, PARP-1 cleavage and estimation of the sub-G 1 cell fraction. Results : Of the eight A-T LCL tested, all harbouring truncating ATM mutations, five had a higher level of spontaneous apoptosis than the normal LCL as assessed by the sub-G 1 cell fraction. Four of the eight A-T LCLs showed a similar level of radiation-induced apoptosis after exposure to 5 Gy as the normal LCL. The other four A-T LCL showed a greater radiation-induced apoptotic response, as assessed by at least one of the three techniques. Conclusions : LCL from A-T patients can undergo ionizing radiation-induced apoptosis in spite of a defect in ATM-p53-dependent signalling pathways. However, the apoptotic response is characterized by a large degree of variability between the A-T cell lines, the causes of which remain to be established.     

Attenuated early inflammatory response in solid organ recipients with COVID-19

Immunosuppression leaves transplanted patients at particular risk for severe acute respiratory syndrome 2 (SARS-CoV-2) infection. The specific features of coronavirus disease 2019 (COVID-19) in immunosuppressed patients are largely unknown and therapeutic experience is lacking. Seven transplanted patients (two liver, three kidneys, one double lung, one heart) admitted to the Ludwig-Maximilians-University Munich because of COVID-19 and tested positive for SARS-CoV-2 were included. The clinical course and the clinical findings were extracted from the medical record. The two liver transplant patients and the heart transplant patient had an uncomplicated course and were discharged after 14, 18, and 12 days, respectively. Two kidney transplant recipients were intubated within 48 hours. One kidney and the lung transplant recipients were required to intubate after 10 and 15 days, respectively. Immunosuppression was adapted in five patients, but continued in all patients. Compared to non-transplanted patients at the ICU (n = 19) the inflammatory response was attenuated in transplanted patients, which was proven by decreased IL-6 blood values. This analysis might provide evidence that continuous immunosuppression is safe and probably beneficial since there was no hyperinflammation evident. Although transplanted patients might be more susceptible to an infection with SARS-CoV-2, their clinical course seems to be similar to immunocompetent patients.     

Resection of Pulmonary Metastases from Colon and Rectal Cancer: Factors to Predict Survival Differ Regarding to the Origin of the Primary Tumor

Background

The purpose of the present study was to determine differences in prognostic factors for survival of patients with pulmonary metastases resected in curative intent from colon or rectum cancer.

Methods

Between 1980 and 2006, prognostic factors after resection of pulmonary metastases in 171 patients with primary rectum or colon tumor were evaluated. Survival of patients after surgical metastasectomy was compared with that of patients receiving standard chemotherapy by matched-pair analysis.

Results

Median survival after pulmonary resection was 35.2 months (confidence interval 27.3–43.2). One-, 3-, and 5-year survival for patients following R0 resection was 88.8, 52.1, and 32.9 % respectively. Complete metastasectomy (R0), UICC stage of the primary tumor, pleural infiltration, and hilar or mediastinal lymph node metastases are independent prognostic factors for survival. Matched-pair analysis confirmed that pulmonary metastasectomy significantly improved survival. Although no difference in survival for patients with pulmonary metastases from lower rectal compared to upper rectal or colon cancer was observed, factors to predict survival are different for patients with lower and middle rectal cancer (R0, mediastinal and/or hilar lymph nodes, gender, UICC stage) compared with patients with upper rectal or colon cancer (R0, number of metastases).

Conclusions

Our results indicate that distinct prognostic factors exist for patients with pulmonary metastases from lower rectal compared with upper rectal or colon cancer. This supports the notion that colorectal cancer should not be considered as a single-tumor entity. Metastasectomy, especially after complete resection resulted in a dramatic improvement of survival compared with patients treated with chemotherapy alone.     

Angiogenesis in cancer: molecular mechanisms,clinical impact

Background Angiogenesis, the formation of new blood vessels from the endothelium of the existing vasculature, is fundamental in tumor growth, progression, and metastasis. Inhibiting tumor angiogenesis is a promising strategy for treatment of cancer and has been successfully transferred from preclinical to clinical application in recent years. Whereas conventional therapeutic approaches, e.g. chemotherapy and radiation, are focussing on tumor cells, antiangiogenic therapy is directed against the tumor supplying blood vessels. Materials and methods This review will summarize important molecular mechanisms of tumor angiogenesis and advances in the design of antiangiogenic drugs. Furthermore, clinical implications of antiangiogenic therapy in surgical oncology will be discussed. Results First antiangiogenic drugs have been approved for treatment of advanced solid tumors in several countries. Leading antiangiogenic drugs are designed to inhibit vascular endothelial growth factor-mediated tumor angiogenesis. Combining antiangiogenic agents with conventional chemotherapy or radiation is currently investigated clinically with great emphasis to realize a multimodal tumor therapy, targeting both the tumor cell and tumor vascular compartment. Conclusion Antiangiogenic tumor therapy represents a promising strategy for treatment of cancer and will most likely exhibit its clinical potential in combination with established standard tumor therapies in the future.     

Surface engineering of stainless steel materials by covalent collagen immobilization to improve implant biocompatibility

It was shown recently that the deposition of thin films of tantalum and tantalum oxide enhanced the long-term biocompatibility of stainless steel biomaterials due to an increase in their corrosion resistance. In this study, we used this tantalum oxide coating as a basis for covalent immobilization of a collagen layer, which should result in a further improvement of implant tissue integration. Because of the high degradation rate of natural collagen in vivo, covalent immobilization as well as carbodiimide induced cross-linking of the protein was performed. It was found that the combination of the silane-coupling agent aminopropyl triethoxysilane and the linker molecule N,N'-disulphosuccinimidyl suberate was a very effective system for collagen immobilizing. Mechanical and enzymatic stability testing revealed a higher stability of covalent bound collagen layers compared to physically adsorbed collagen layers. The biological response induced by the surface modifications was evaluated by in vitro cell culture with human mesenchymal stem cells as well as by in vivo subcutaneous implantation into nude mice. The presence of collagen clearly improved the cytocompatibility of the stainless steel implants which, nevertheless, significantly depended on the cross-linking degree of the collagen layer.     

The synergy of clinical placements

As we move to accommodate the demands for placement and move students from a learner to a professional role, all parties in a student's clinical learning situation need to re-examine traditional ways of doing things to see if they are still the most effective. The results of placing and working with students in a way that is collaborative and more student-driven may be surprising. The benefits could well outweigh the costs in terms of long-range goals for faculty, students and agencies.