A novel bioprinting method and system for forming hybrid tissue engineering constructs.

Three dimensional (3D) bioprinting is a promising approach to form tissue engineering constructs (TECs) via positioning biomaterials, growth factors, and cells with controlled spatial distribution due to its layer-by-layer manufacturing nature. Hybrid TECs composed of relatively rigid porous scaffolds for structural and mechanical integrity and soft hydrogels for cell- and growth factor-loading have a tremendous potential to tissue regeneration under mechanical loading. However, despite excessive progress in the field, the current 3D bioprinting techniques and systems fall short in integration of such soft and rigid multifunctional components. Here we present a novel 3D hybrid bioprinting technology (Hybprinter) and its capability enabling integration of soft and rigid components for TECs. Hybprinter employs digital light processing-based stereolithography (DLP-SLA) and molten material extrusion techniques for soft and rigid materials, respectively. In this study, poly-ethylene glycol diacrylate (PEGDA) and poly-(ε-caprolactone) (PCL) were used as a model material for soft hydrogel and rigid scaffold, respectively. It was shown that geometrical accuracy, swelling ratio and mechanical properties of the hydrogel component can be tailored by DLP-SLA module. We have demonstrated the printability of variety of complex hybrid construct designs using Hybprinter technology and characterized the mechanical properties and functionality of such constructs. The compressive mechanical stiffness of a hybrid construct (90% hydrogel) was significantly higher than hydrogel itself (∼6 MPa versus 100 kPa). In addition, viability of cells incorporated within the bioprinted hybrid constructs was determined approximately 90%. Furthermore, a functionality of a hybrid construct composed of porous scaffold with an embedded hydrogel conduit was characterized for vascularized tissue engineering applications. High material diffusion and high cell viability in about 2.5 mm distance surrounding the conduit indicated that culture media effectively diffused through the conduit and fed the cells. The results suggest that the developed technology is potent to form functional TECs composed of rigid and soft biomaterials.

Paclitaxel-ifosfamide for anthracycline-resistant advanced breast cancer.

Thirty-one patients with advanced breast cancer either resistant to anthracycline-based regimens or relapsing after anthracycline-based adjuvant chemotherapy received a combination of a 3-h infusion of paclitaxel 135 mg/m2 on day 1 and a 4-h infusion of ifosfamide 1.7 g/m2 on days 2 to 4 of a 22-day cycle. For inclusion in the study, patients had to have measurable or evaluable progressive metastasis or local disease, and to have received only one prior regimen for metastatic disease; 31 patients with a median age of 49 years (range: 30-69) entered the study. Nine patients (29%) had lung metastasis, while 17 (55%) had liver metastasis, and 19 (61%) had bone metastasis. Only seven patients (23%) had lymph node metastasis and four (13%) had skin metastasis. A median of seven cycles of treatment was delivered. Responses were evaluated according to World Health Organization (WHO) guidelines and side effects according to National Cancer Institute (NCI) criteria. A panel of oncologists and one radiologist reviewed all responses. At baseline, only three patients (10%) were free from the adverse effects of the prior therapy; severe nonhematological toxicity occurred in less than 8% of patients. However neutropenia grade 3-4 occurred in 88%, while only 3% had severe infections. Severe thrombocytopenia and anemia were rare (4% and 8%, respectively). The overall response rate was 42% (13% complete response). Median survival and progression-free survival rates after initiation of treatment were 19.3 months and 6.1 months, respectively. With an objective response rate of 42% and median survival of 19 months, the combination of paclitaxel and ifosfamide seems to offer a promising regimen with acceptable side effects in advanced breast cancer patients relapsing after anthracycline-based adjuvant treatment or resistant to anthracycline treatment.

Omission of histologic grading from clinical decision making may result in overuse of adjuvant therapies in breast cancer: results from a nationwide study.

PURPOSE: To investigate the influence of routinely performed histologic grading on breast cancer outcome prediction and patient selection for adjuvant therapy. PATIENTS AND METHODS: The analysis is based on a cohort of 2,842 women diagnosed with breast cancer and comprising 91% of all breast cancers diagnosed in five defined geographical regions in Finland in 1991 through 1992. Data on clinicopathologic factors and follow-up were collected from hospital case records and national registries. Histologic grade assessed at diagnosis and other clinicopathologic data were available for 1,554 operable unilateral invasive carcinomas. The relative value of grade with respect to competing prognostic factors was estimated with the Cox proportional hazards model and logistic regression. Interactions and nonlinearity of factors were accounted for by using an artificial neural network. RESULTS: Histologic grade was correlated strongly with survival in the entire series and in all subgroups studied. Women with well-differentiated node-negative cancer had a 97% 5-year distant disease-free survival rate as compared with 78% for women with poorly differentiated cancer. Grade was an independent prognostic factor in multivariate models and increased the predictive accuracy of a neural network model. Inclusion of grade data in a Cox multivariate model based on tumor size and hormone receptor status in node-negative cancer increased the proportion of patients with 5% or less risk for distant recurrence at 5 years from 15% to 54%. CONCLUSION: Even when assessed by pathologists who have no special training in breast cancer pathology, histologic grade has substantial and independent prognostic value in breast cancer. Omission of grading from clinical decision making may result in considerable overuse of adjuvant therapies.

Paclitaxel-induced apoptotic changes followed by time-lapse video microscopy in cell lines established from head and neck cancer.

Paclitaxel (Taxol) is a potent chemotherapeutic drug for squamous-cell carcinoma (SCC) of the head and neck in vitro with microtubule-stabilizing activity that arrests cells in G2-M. To study the mechanism of its cytotoxic effect on SCC in vitro, we exposed five laryngeal SCC cell lines to 10 nM paclitaxel. The cell lines were studies by time-lapse video microscopy for 96 h, and by agarose gel electrophoresis. Paclitaxel blocked the cells in the premitotic phase for 6-24 h, after which the cells died morphologically by apoptosis. Mitotically arrested cells were seen within a few minutes after exposure to paclitaxel. No mitoses were seen in the paclitaxel-treated cells. A few apoptoses were also seen in the control cultures grown without paclitaxel, but they represented only 6%-20% of the frequency of apoptoses seen in the paclitaxel-treated group. In some paclitaxel-treated cultures the cells escaped the mitotic arrest without cytokinesis and formed multinucleated cells that eventually died. Agarose gel electrophoresis showed oligonucleosomal DNA fragmentation characteristic of apoptosis. We conclude that time-lapse video microscopy is an efficient method of observing drug-induced morphological changes in cell culture. Paclitaxel at a 10 nM concentration rapidly induces a premitotic block, which usually leads to apoptotic cell death. In some cases multinucleated cells are formed that morphologically also eventually die by apoptosis.

Squamous cell carcinoma is highly sensitive to taxol, a possible new radiation sensitizer.

We studied the sensitivity of seven cell lines established from laryngeal carcinoma to the cytotoxic drug paclitaxel (Taxol) in vitro. In all four cell lines tested for growth inhibition, paclitaxel reduced growth at low concentrations, and in two cell lines growth was completely inhibited at a paclitaxel concentration of only 1 x 10(-8) M. Flow cytometric data showed a G2/M block in all seven cell lines after exposure to paclitaxel for 24 h at a concentration of 1 x 10(-8) M. This concentration is about one-one hundredth fold smaller than those measured in serum after a single intravenous dose of about 200 mg/m2. The high in vitro sensitivity of laryngeal cancer cell lines to paclitaxel,and the G2/M block suggest that the drug may potentially be used in conjunction with radiotherapy.

[The concept of man in nursing education: evaluation of the students' answers to the exam questions in nursing]. / Hoito-opin opetuksessa välittyvä käsitys ihmisestä: opiskelijoiden koevastausten arviointia.

The purpose of the study was to describe the concept of man in nursing education. The data consisted of the nursing students' answers to the summative exam questions in seven courses in nursing. The total number of answers in the study was 202. The data was analyzed by the method of content analysis. Four dimensions of the concept of man were formed on the basis of the theoretical background: the holistic concept of man, the reduced concept of man, man as an active subject, man as a passive object. From the answers 40% described man as a holistic, active subject and 30% as a reduced, passive object. Man as a holistic, passive object was identified in 16% of the answers and as a reduced, active subject in the rest. The holistic concept of man was expressed as a bio-psychosocial wholeness. The reduced concept meant that man was described mostly as a biological organism. The activity of man was described as concrete activity, man was not described as a decision maker.