Antisenescence Effect of REAC Biomodulation to Counteract the Evolution of Myelodysplastic Syndrome

About 30 percent of patients diagnosed with myelodysplastic syndromes (MDS) progress to acute myeloid leukemia (AML). The senescence of bone marrow‐derived mesenchymal stem cells (BMSCs) seems to be one of the determining factors in inducing this drift. Research is continuously looking for new methodologies and technologies that can use bioelectric signals to act on senescence and cell differentiation towards the phenotype of interest. The Radio Electric Asymmetric Conveyer (REAC) technology, aimed at reorganizing the endogenous bioelectric activity, has already shown to be able to determine direct cell reprogramming effects and counteract the senescence mechanisms in stem cells. Aim of the present study was to prove if the anti-senescence results previously obtained in different kind of stem cells with the REAC Tissue optimization – regenerative (TO-RGN) treatment, could also be observed in BMSCs, evaluating cell viability, telomerase activity, p19ARF, P21, P53, and hTERT gene expression. The results show that the REAC TO-RGN treatment may be a useful tool to counteract the BMSCs senescence which can be the basis of AML drift. Nevertheless, further clinical studies on humans are needed to confirm this hypothesis.

Monte Carlo simulations and phantom validation of low-dose radiotherapy to the lungs using an interventional radiology C-arm fluoroscope

PURPOSE

To use MC simulations and phantom measurements to investigate the dosimetry of a kilovoltage x-ray beam from an IR fluoroscope to deliver low-dose (0.3-1.0 Gy) radiotherapy to the lungs.

MATERIALS AND METHODS

PENELOPE was used to model a 125 kV, 5.94 mm Al HVL x-ray beam produced by a fluoroscope. The model was validated through depth-dose, in-plane/cross-plane profiles and absorbed dose at 2.5-, 5.1-, 10.2- and 15.2-cm depths against the measured beam in an acrylic phantom. CT images of an anthropomorphic phantom thorax/lungs were used to simulate 0.5 Gy dose distributions for PA, AP/PA, 3-field and 4-field treatments. DVHs were generated to assess the dose to the lungs and nearby organs. Gafchromic film was used to measure doses in the phantom exposed to PA and 4-field treatments, and compared to the MC simulations.

RESULTS

Depth-dose and profile results were within 3.2% and 7.8% of the MC data uncertainty, respectively, while dose gamma analysis ranged from 0.7 to 1.0. Mean dose to the lungs were 1.1-, 0.8-, 0.9-, and 0.8- Gy for the PA, AP/PA, 3-field, and 4-field after isodose normalization to cover ∼ 95% of each lung volume. Skin dose toxicity was highest for the PA and lowest for the 4-field, and both arrangements successfully delivered the treatment on the phantom. However, the dose distribution for the PA was highly non-uniform and produced skin doses up to 4 Gy. The dose distribution for the 4-field produced a uniform 0.6 Gy dose throughout the lungs, with a maximum dose of 0.73 Gy. The average percent difference between experimental and Monte Carlo values were -0.1% (range -3% to +4%) for the PA treatment and 0.3% (range -10.3% to +15.2%) for the 4-field treatment.

CONCLUSION

A 125 kV x-ray beam from an IR fluoroscope delivered through two or more fields can deliver an effective low-dose radiotherapy treatment to the lungs. The 4-field arrangement not only provides an effective treatment, but also significant dose sparing to healthy organs, including skin, compared to the PA treatment. Use of fluoroscopy appears to be a viable alternative to megavoltage radiation therapy equipment for delivering low-dose radiotherapy to the lungs.

Vertebral formula and congenital abnormalities of the vertebral column in rabbits

The aim of this retrospective study of 330 rabbits (164 males, 166 females) was to determine different vertebral formulas and prevalence of congenital vertebral anomalies in rabbits from radiographs of the cervical (C), thoracic (Th), lumbar (L) and sacral (S) segments of the vertebral column. The number of vertebrae in each segment of vertebral column, position of anticlinal vertebra and localisation and type of congenital abnormalities were recorded. In 280/330 rabbits (84.8%) with normal vertebral morphology, seven vertebral formulas were identified: C7/Th12/L7/S4 (252/330, 76.4%), C7/Th12/L6/S4 (11/330, 3.3%), C7/Th13/L7/S4 (8/330, 2.4%), C7/Th12/L7/S5 (4/330, 1.2%), C7/Th12/L8/S4 (3/330, 0.9%), C7/Th12/L7/S6 (1/330, 0.3%) and C7/Th11/L7/S4 (1/330, 0.3%). The anticlinal vertebra was identified as Th10 in 56.4% of rabbits and Th11 in 42.4% of rabbits. Congenital spinal abnormalities were identified in 50/330 (15.2%) rabbits, predominantly as a single pathology (n=44). Transitional vertebrae represented the most common abnormalities (n=41 rabbits) in the thoracolumbar (n=35) and lumbosacral segments (n=6). Five variants of thoracolumbar transitional vertebrae were identified. Cervical butterfly vertebrae were detected in three rabbits. One rabbit exhibited three congenital vertebral anomalies: cervical block vertebra, thoracic hemivertebra and thoracolumbar transitional vertebra. Five rabbits exhibited congenital vertebral abnormalities with concurrent malalignment, specifically cervical kyphosis/short vertebra (n=1), thoracic lordoscoliosis/thoracolumbar transitional vertebrae (n=1), thoracic kyphoscoliosis/wedge vertebrae (n=2) and thoracolumbar lordoscoliosis/thoracolumbar transitional vertebrae/lumbosacral transitional vertebrae (n=1). These findings suggest that vertebral columns in rabbits display a wide range of morphologies, with occasional congenital malformations.

A low prevalence of mycobacteria in freshwater fish from water reservoirs, ponds and farms

A survey of the occurrence of mycobacteria was conducted from 717 freshwater fish (25 species) in two water reservoirs, five ponds and two farms in the Czech Republic. A total of 2182 tissue samples from these fish were examined using the conventional culture method. Thirteen mycobacterial isolates were obtained from 12 (1.7%) fish belonging to nine species. Isolates were identified using sequence analysis of the 16SrRNA gene as: Mycobacterium algericum, M. fortuitum, M. gordonae, M. insubricum, M. kumamotonense, M. nonchromogenicum, two isolates of M. peregrinum, M. terrae and M. triplex. Mycobacteria were isolated more frequently from fish skin and gills than from internal organs or muscles.

Field reversed configuration confinement enhancement through edge biasing and neutral beam injection

Field reversed configurations (FRCs) with high confinement are obtained in the C-2 device by combining plasma gun edge biasing and neutral beam injection. The plasma gun creates an inward radial electric field that counters the usual FRC spin-up. The n = 2 rotational instability is stabilized without applying quadrupole magnetic fields. The FRCs are nearly axisymmetric, which enables fast ion confinement. The plasma gun also produces E × B shear in the FRC edge layer, which may explain the observed improved particle transport. The FRC confinement times are improved by factors 2 to 4, and the plasma lifetimes are extended from 1 to up to 4 ms.

Dynamic formation of a hot field reversed configuration with improved confinement by supersonic merging of two colliding high-β compact toroids

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-β plasmoids preformed by the dynamic version of field-reversed θ-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{i}+T{e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Quality of newly formed cartilaginous tissue in defects of articular surface after transplantation of mesenchymal stem cells in a composite scaffold based on collagen I with chitosan micro- and nanofibres

The aim of this study was to evaluate macroscopically, histologically and immunohistochemically the quality of newly formed tissue in iatrogenic defects of articular cartilage of the femur condyle in miniature pigs treated with the clinically used method of microfractures in comparison with the transplantation of a combination of a composite scaffold with allogeneic mesenchymal stem cells (MSCs) or the composite scaffold alone. The newly formed cartilaginous tissue filling the defects of articular cartilage after transplantation of the scaffold with MSCs (Group A) had in 60 % of cases a macroscopically smooth surface. In all lesions after the transplantation of the scaffold alone (Group B) or after the method of microfractures (Group C), erosions/fissures or osteophytes were found on the surface. The results of histological and immunohistochemical examination using the modified scoring system according to O'Driscoll were as follows: 14.7+/-3.82 points after transplantations of the scaffold with MSCs (Group A); 5.3+/-2.88 points after transplantations of the scaffold alone (Group B); and 5.2+/-0.64 points after treatment with microfractures (Group C). The O'Driscoll score in animals of Group A was significantly higher than in animals of Group B or Group C (p<0.0005 both). No significant difference was found in the O'Driscoll score between Groups B and C. The treatment of iatrogenic lesions of the articular cartilage surface on the condyles of femur in miniature pigs using transplantation of MSCs in the composite scaffold led to the filling of defects by a tissue of the appearance of hyaline cartilage. Lesions treated by implantation of the scaffold alone or by the method of microfractures were filled with fibrous cartilage with worse macroscopic, histological and immunohistochemical indicators.

Use of allogenic stem cells for the prevention of bone bridge formation in miniature pigs

This study appears from an experiment previously carried out in New Zealand white rabbits. Allogenic mesenchymal stem cells (MSCs) were transplanted into an iatrogenically-created defect in the lateral section of the distal physis of the left femur in 10 miniature pigs. The right femur with the same defect served as a control. To transfer MSCs, a freshly prepared porous scaffold was used, based on collagen and chitosan, constituting a compact tube into which MSCs were implanted. The pigs were euthanized four months after the transplantation. On average, the left femur with transplanted MSCs grew more in length (0.56+/-0.14 cm) compared with right femurs with physeal defect without transplanted MSCs (0.14+/-0.3 cm). The average angular (valgus) deformity of the left femur had an angle point of 0.78 degrees , following measurement and X-ray examination, whereas in the right femur without transplantation it was 3.7 degrees. The initial results indicate that preventive transplantation of MSCs into a physeal defect may prevent valgus deformity formation and probably also reduce disorders of the longitudinal bone growth. This part of our experiment is significant in the effort to advance MSCs application in human medicine by using pig as a model, which is the next step after experimenting on rabbits.

[New options for management of posttraumatic articular cartilage defects]

Articular cartilage trauma, in particular due to its poor healing potential remains a complicated problem in both the adult and paediatric traumatology and orthopedics. In older patients, total endoprosthesis of the joint is a method of choice, however, in younger patients, the situation remains more complicated. In case of osteochondral lesions (arthrosis, chondral fractures. osteochoodrosis dissecns) the ideal management should result in complete recovery of the hyaline cartilage on the traumatized joint surface. Contemporary medicine uses some therapeutic procedures resulting in partial recovery of the articular cartilage structure at the lesion site and several techniques of excisionining the articular surface's injured part and of transplantations of biological grafts. Regarding the above first approach, abrasive methods (micro fractures, small drill holes), which are expected to result in recovery of the articular cartilage through progenitor cells that migrate from the bone marrow to the defect site following subchondral fracturing. In case the injury is managed early, the osteochondral fragment may be fixed and the articular congruence be recovered. Mosaicoplasty using osteochondral auto grafts or other autologous grafts, or more recently using transplantations of autologous chond rocytes, which seem to have a major potential in the hyaline cartilage healing process. However, methodology of the transplant retention at the defect site remains a problem. Furthermore, the use of mesenchymal stem cells, so far in the experimental phase, appears prospective. Pivotal articular cartilage treatment research activities have progressed to a level of searching for a suitable scaffold of perfect qualities. This is the task for cooperation with bioengineering. requiring provision of the most exact differentiation protocol for hyline cartilage producing mesenchymal stem cells (MSCs).

Use of 3D geometry modeling of osteochondrosis-like iatrogenic lesions as a template for press-and-fit scaffold seeded with mesenchymal stem cells

Computed tomography (CT) is an effective diagnostic modality for three-dimensional imaging of bone structures, including the geometry of their defects. The aim of the study was to create and optimize 3D geometrical and real plastic models of the distal femoral component of the knee with joint surface defects. Input data included CT images of stifle joints in twenty miniature pigs with iatrogenic osteochondrosis-like lesions in medial femoral condyle of the left knee. The animals were examined eight and sixteen weeks after surgery. Philips MX 8000 MX and View workstation were used for scanning parallel plane cross section slices and Cartesian discrete volume creation. On the average, 100 slices were performed in each stifle joint. Slice matrices size was 512 x 512 with slice thickness of 1 mm. Pixel (voxel) size in the slice plane was 0.5 mm (with average accuracy of +/-0.5 mm and typical volume size 512 x 512 x 100 voxels). Three-dimensional processing of CT data and 3D geometrical modelling, using interactive computer graphic system MediTools formerly developed here, consisted of tissue segmentation (raster based method combination and 5 % of manual correction), vectorization by the marching-cubes method, smoothing and decimation. Stifle- joint CT images of three individuals of different body size (small, medium and large) were selected to make the real plastic models of their distal femurs from plaster composite using rapid prototyping technology of Zcorporation. Accuracy of the modeling was +/- 0.5 mm. The real plastic models of distal femurs can be used as a template for developing custom made press and fit scaffold implants seeded with mesenchymal stem cells that might be subsequently implanted into iatrogenic joint surface defects for articular cartilage-repair enhancement.

Biochemical and biophysical aspects of collagen nanostructure in the extracellular matrix

ECM is composed of different collagenous and non-collagenous proteins. Collagen nanofibers play a dominant role in maintaining the biological and structural integrity of various tissues and organs, including bone, skin, tendon, blood vessels, and cartilage. Artificial collagen nanofibers are increasingly significant in numerous tissue engineering applications and seem to be ideal scaffolds for cell growth and proliferation. The modern tissue engineering task is to develop three-dimensional scaffolds of appropriate biological and biomechanical properties, at the same time mimicking the natural extracellular matrix and promoting tissue regeneration. Furthermore, it should be biodegradable, bioresorbable and non-inflammatory, should provide sufficient nutrient supply and have appropriate viscoelasticity and strength. Attributed to collagen features mentioned above, collagen fibers represent an obvious appropriate material for tissue engineering scaffolds. The aim of this minireview is, besides encapsulation of the basic biochemical and biophysical properties of collagen, to summarize the most promising modern methods and technologies for production of collagen nanofibers and scaffolds for artificial tissue development.

Biomechanical characterization of cartilages by a novel approach of blunt impact testing

The present article introduces a novel method of characterizing the macromechanical cartilage properties based on dynamic testing. The proposed approach of instrumented impact testing shows the possibility of more detailed investigation of the acting dynamic forces and corresponding deformations within the wide range of strain rates and loads, including the unloading part of stress-strain curves and hysteresis loops. The presented results of the unconfined compression testing of both the native joint cartilage tissues and potential substitute materials outlined the opportunity to measure the dissipation energy and thus to identify the initial mechanical deterioration symptoms and to introduce a better definition of material damage. Based on the analysis of measured specimen deformation, the intact and pathologically changed cartilage tissue can be distinguished and the differences revealed.

Mechanical response of porous scaffolds for cartilage engineering

Mechanical properties of scaffolds seeded with mesenchymal stem cells used for cartilage repair seem to be one of the critical factors in possible joint resurfacing. In this paper, the effect of adding hyaluronic acid, hydroxyapatite nanoparticles or chitosan nanofibers into the cross-linked collagen I on the mechanical response of the lyophilized porous scaffold has been investigated in the dry state at 37 oC under tensile loading. Statistical significance of the results was evaluated using ANOVA analysis. The results showed that the addition of hyaluronic acid significantly (p<<0.05) reduced the tensile elastic modulus and enhanced the strength and deformation to failure of the modified cross-linked collagen I under the used test conditions. On the other hand, addition of hydroxyapatite nanoparticles and chitosan nanofibers, respectively, increased the elastic modulus of the modified collagen ten-fold and four-fold, respectively. Hydroxyapatite caused significant reduction in the ultimate deformation at break while chitosan nanofibers enhanced the ultimate deformation under tensile loading substantially (p<<0.05). The ultimate tensile deformation was significantly (p<<0.05) increased by addition of the chitosan nanofibers. The enhanced elastic modulus of the scaffold was translated into enhanced resistance of the porous scaffolds against mechanical load compared to scaffolds based on cross-linked neat collagen or collagen with hyaluronic acid with similar porosity. It can be concluded that enhancing the rigidity of the compact scaffold material by adding rigid chitosan nanofibers can improve the resistance of the porous scaffolds against compressive loading, which can provide more structural protection to the seeded mesenchymal stem cells when the construct is implanted into a lesion. Moreover, scaffolds with chitosan nanofibers seemed to enhance cell growth compared to the neat collagen I when tested in vitro as well as the scaffold stability, extending its resorption to more than 10 weeks.

Subtotal intracapsular prostatectomy as a useful treatment for advanced-stage prostatic malignancies

OBJECTIVES

Palliative surgery for advanced-stage prostatic cancers was tested with regard to survival rate and complications in a prospective randomised clinical study of dogs. Currently, therapeutic approaches have a grave long-term prognosis in clinically significant prostatic cancer.

METHODS

Of 167 dogs with prostatic disorders, 24 were diagnosed with prostatic cancer. Eleven dogs underwent subtotal intracapsular prostatectomy, while in 10 dogs total prostatectomy was performed. The remaining three dogs were euthanased at their owner's request. Dogs treated by subtotal intracapsular prostatectomy and those treated by total prostatectomy were followed until their death.

RESULTS

It was found that dogs treated by subtotal intracapsular prostatectomy survived 5.63 times longer (mean [sd] 112.0 [63.03] days) than those treated by total prostatectomy (19.9 [10.67] days) (P<0.01). Moreover, a significant decrease in postoperative complications after subtotal intracapsular prostatectomy was recorded, especially with regard to urinary incontinence.

CLINICAL SIGNIFICANCE

It was concluded that, in the authors' facility, treatment of prostatic cancer by subtotal intracapsular prostatectomy was superior to that by total prostatectomy, with respect to both postoperative survival and serious complications.

[Neurosurgical therapy of intervertebral disk disease in dogs]

Intervertebral disc degeneration and protrusion or extrusion of disc material into the vertebral canal cause focal compressive myelopathy and radiculopathy, the most common neurological syndrome in dogs. Clinical findings are variable depending on duration and location of the lesion, volume of the mass and dynamic considerations (peracute massive extrusion, chronic partial extrusion, chronic progressive extrusion). Aim of this article is to provide compendium of at-the-present-time recommended methods of surgical treatment of intervertebral disc disease in the dog. In the case of compression of spinal cord is performed decompressive surgery (ventral cervical decompression, hemilaminectomy, minihemilaminectomy, dorsal laminectomy and foramenotomy). Fenestration is the only method of prophylaxis.

[Results of surgical treatment in disorders of the thoracolumbar disks in dogs]

The clinical records of 90 dogs with thoracolumbar disc disease treated by fenestration or decompressive surgery on Surgical Department of the University of Veterinary and Pharmaceutical Sciences in Brno between September 1992 and March 1994 were reviewed. The breed, age and sex predisposition, rate of disc protrusion or extrusion and number of multiple disc extrusions were recorded. The frequency of disc protrusion/extrusion at each intervertebral space in thoracolumbar region of spine was also observed. Dogs were grouped by clinical signs of disease in four groups. Recovery rates depending on the pre-operative neurological grade of spinal injury and duration of clinical signs were compared. Patients were observed at least 6 months after surgery and the results of therapy were classified as good (complete recovery of motor and urinary function), fair (some remaining dysfunction, either motor or urinary, but animal retained independent function and usefulness) and poor (not enough improvement to be returned to the owner as an independent animal). Eight breeds and mixed-breed dogs were represented in the 90 cases of thoracolumbar disc disease. Shorthaired Dachshunds predominated (58.9%). The age range of dogs was 3-12 years; 52% were males and 48% females. Incidence of disc protrusion was 13.3% and disc extrusion 86.6% of the cases, with the frequency 3.3% of multiple disc extrusions. The most common site of lesion was the T12-T13 interspace. Twelve dogs in group II were treated by fenestration with good results of therapy in all cases. There was no recurrence of clinical signs during period of observation.(ABSTRACT TRUNCATED AT 250 WORDS)