94 research outputs found
A cartilage tissue engineering approach combining starch-polycaprolactone fibre mesh scaffolds with bovine articular chondrocytes
In the present work we originally tested the suitability
of corn starch-polycaprolactone (SPCL) scaffolds for
pursuing a cartilage tissue engineering approach. Bovine articular
chondrocytes were seeded on SPCL scaffolds under
dynamic conditions using spinner flasks (total of 4 scaffolds
per spinner flask using cell suspensions of 0.5×106 cells/ml)
and cultured under orbital agitation for a total of 6 weeks.
Poly(glycolic acid) (PGA) non-woven scaffolds and bovine
native articular cartilage were used as standard controls for
the conducted experiments. PGA is a kind of standard in
tissue engineering approaches and it was used as a control
in that sense. The tissue engineered constructs were characterized
at different time periods by scanning electron microscopy
(SEM), hematoxylin-eosin (H&E) and toluidine
blue stainings, immunolocalisation of collagen types I and II,
and dimethylmethylene blue (DMB) assay for glycosaminoglycans
(GAG) quantification assay. SEM results for SPCL
constructs showed that the chondrocytes presented normal
morphological features, with extensive cells presence at the
surface of the support structures, and penetrating the scaffolds
pores. These observations were further corroborated
by H&E staining. Toluidine blue and immunohistochemistry
exhibited extracellular matrix deposition throughout the 3D structure. Glycosaminoglycans, and collagen types I and II
were detected. However, stronger staining for collagen type
II was observed when compared to collagen type I. The PGA
constructs presented similar features toSPCLat the end of the
6 weeks. PGA constructs exhibited higher amounts of matrix
glycosaminoglycans when compared to the SPCL scaffolds.
However, we also observed a lack of tissue in the central
area of the PGA scaffolds. Reasons for these occurrences
may include inefficient cells penetration, necrosis due to high
cell densities, or necrosis related with acidic by-products
degradation. Such situation was not detected in the SPCL
scaffolds, indicating the much better biocompatibility of the
starch based scaffolds
Reinforcing the role of the conventional C-arm - a novel method for simplified distal interlocking
<p>Abstract</p> <p>Background</p> <p>The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure.</p> <p>Methods</p> <p>The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required.</p> <p>Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests.</p> <p>Results</p> <p>A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (<it>p </it>< 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (<it>p </it>= 0.001). Operating time per screw (from first shot to screw tightened) was on average 22% reduced by guided freehand (<it>p </it>= 0.018).</p> <p>Conclusions</p> <p>In an experimental setting, the newly developed guided freehand technique for distal interlocking has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method utilizes established clinical workflows and does not require cost intensive add-on devices or extensive training. The underlying principle carries potential to assist implant positioning in numerous other applications within orthopedics and trauma from screw insertions to placement of plates, nails or prostheses.</p
Immunophenotypic predictive profiling of BRCA1-associated breast cancer
The immunophenotypic predictive profile of BRCA1-associated cancers including major predictive markers, i.e., PARP-1, EGFR, c-kit, HER-2, and steroid hormones (ER/PR) that may have therapeutic relevance has not yet been reported in a comprehensive study. Using immunohistochemistry, we examined the expression of these proteins in a large cohort of BRCA1-associated breast cancers. PARP-1 immunoreactivity was found in 81.9%, EGFR in 43.6%, ER/PR in 17.9%, c-kit in 14.7%, and overexpression of HER-2 in 3.6% of cancers. For all markers studied, 8.2% of tumors were negative. Expression of only one predictive marker was found in 29.7% of cancers, and most frequently, it was PARP-1 (20.8%). In 62.1% of tumors, more than one predictive marker was expressed: PARP-1 and EGFR in 30.4%, PARP-1, and hormone receptors in 13.3% and PARP-1 with c-kit in 7.5% of all tumors. Coexpression of two or more other predictive markers was rare. There were significant differences in the median age at diagnosis of BRCA1-associated cancer between patients with ER+ vs. ER− and grades 1–2 vs. grade 3 tumors. These results demonstrate that BRCA1-associated cancers differ with respect to expression of proteins that are regarded as targets for specific therapies and that 92% of patients with BRCA1-associated cancers may benefit from one or several options for specific therapy (in addition to DNA damaging agents, e.g., cisplatin). About 8% of cancers which do not express therapeutic target proteins may not respond to such therapies. Knowledge of the immunophenotypic predictive profile may help with the recruitment of patients for trials of targeted therapies
Gene-enhanced tissue engineering for dental hard tissue regeneration: (1) overview and practical considerations
Gene-based therapies for tissue regeneration involve delivering a specific gene to a target tissue with the goal of changing the phenotype or protein expression profile of the recipient cell; the ultimate goal being to form specific tissues required for regeneration. One of the principal advantages of this approach is that it provides for a sustained delivery of physiologic levels of the growth factor of interest. This manuscript will review the principals of gene-enhanced tissue engineering and the techniques of introducing DNA into cells. Part 2 will review recent advances in gene-based therapies for dental hard tissue regeneration, specifically as it pertains to dentin regeneration/pulp capping and periodontal regeneration
Changes in quality of beech (Fagus sylvatica L.) seeds stored at the Forest Gene Bank Kostrzyca
In the Forest Gene Bank cold stores, both long-term and strategic gene resources are stored to be used during periods of poor seed production. Beech seeds of the following harvests were evaluated: 1995, 1998 and 2000. Quality of seeds was determined with different methods from the date of reception to FGB through preparation for long-term storage, storage in cold stores and the presowing treatment. The usefulness of staining tests for rapid evaluation of beech seed viability is not sufficiently sure. The floating test in water significantly improves the level of seed purity. The current method of seed drying does not remain without influence upon beech seeds and causes a slight decrease of viability. Next to beech seed lots of rapidly declining quality in the FGB are stored seed lots whose viability does not decrease during identical technological processes. Seed lots of low initial viability should be eliminated
Wpływ sposobu uprawy roli i pielęgnacji na zachwaszczenie ziemniaka
A field experiment was conducted in the years 2002-
2004 at the Zawady Agricultural Experimental Station (52o06’
N; 22o06’ E), belonging to the University of Podlasie in Siedlce,
Poland. The investigated factors were two soil tillage systems
(traditional and reduced) and seven methods of weed control
in potato canopies with herbicide application. The aim of the
study was to determine the influence of tillage systems and
weed control methods on the weed species composition and
weed density. Tillage systems, weed control methods and atmospheric
conditions prevailing in the study years significantly
varied weed infestation of potato canopies at the beginning
of vegetation and before tuber harvest. The lowest number of
weeds, compared to the control treatment, was recorded in the
treatments in which chemical and mechanical weed control had
been applied. The treatments with the traditional tillage system
also showed lower weed infestation than those in which simplifications
had been applied.Doświadczenie polowe przeprowadzono w latach
2002-2004 w Rolniczej Stacji Doświadczalnej Zawady
(52o06’ N; 22o06’ E), należącej do Akademii
Podlaskiej w Siedlcach. Badanymi czynnikami były
dwa sposoby uprawy roli (tradycyjna i uproszczona)
i siedem sposobów odchwaszczania łanów ziemniaka
z użyciem herbicydów. Celem badań było określenie
wpływu sposobów uprawy roli i pielęgnacji na skład
gatunkowy i liczebność chwastów. Zachwaszczenie
łanów ziemniaka na początku wegetacji, jak również
przed zbiorem bulw istotnie różnicowały sposoby uprawy,
sposoby pielęgnacji oraz warunki atmosferyczne
występujące w latach badań. Najmniejszą liczbę chwastów
w porównaniu z obiektem kontrolnym zanotowano
na obiektach odchwaszczanych mechaniczno-chemicznie.
Również mniejsze zachwaszczenie wystąpiło
na obiektach z uprawą tradycyjną niż po zastosowaniu
uproszczeń
Economic effectiveness of regulation weed infestation on the potatoes plantations
Celem badań była ocena efektywności ekonomicznej różnych sposobów redukowania zachwaszczenia
w uprawie ziemniaków. Obiekty doświadczenia obejmowały pięć sposobów odchwaszczania:
pielęgnacja mechaniczna i cztery obiekty pielęgnacji mechaniczno-chemicznej z użyciem herbicydów i
ich mieszanin – Command 480 EC, Command 480 EC + Afalon Dyspersyjny 450 SC, Stomp 400 SC,
Stomp 400 SC + Afalon Dyspersyjny 450 SC. Na obiektach odchwaszczanych mechaniczno-chemicznie,
w porównaniu z zabiegami mechanicznymi, uzyskano wzrost plonu handlowego bulw o 70,3-182,7 dt/ha.
Orientacyjne wskaźniki opłacalności (E1 i E2) wykazały, że chemiczna ochrona ziemniaka była opłacalna.This paper presents an assessment of economic efficiency of different methods of reducing weed infestation
in potato cultivation. Experimental objects included five weed control methods: mechanical as well as four
objects of mechanical-chemical treatments with the use of herbicides and their mixtures - Command 480 EC,
Command 480 EC + Afalon Dyspersyjny 450 SC, Stomp 400 SC, Stomp 400 SC + Afalon Dyspersyjny450 SC.
On the mechanical-chemical treated objects, as compared with mechanical weeding, the obtained increase
of market yield of tubers was 70,3-182,7 dt/ha. Orientation indexes of profitability (E1 and E2) indicate that
chemical protection of the potato was profitable
- …