Three-dimensional bio-printing and bone tissue engineering: technical innovations and potential applications in maxillofacial reconstructive surgery

Background Bone grafting has been considered the gold standard for hard tissue reconstructive surgery and is widely used for large mandibular defect reconstruction. However, the midface encompasses delicate structures that are surrounded by a complex bone architecture, which makes bone grafting using traditional methods very challenging. Three-dimensional (3D) bioprinting is a developing technology that is derived from the evolution of additive manufacturing. It enables precise development of a scaffold from different available biomaterials that mimic the shape, size, and dimension of a defect without relying only on the surgeon’s skills and capabilities, and subsequently, may enhance surgical outcomes and, in turn, patient satisfaction and quality of life. Review This review summarizes different biomaterial classes that can be used in 3D bioprinters as bioinks to fabricate bone scaffolds, including polymers, bioceramics, and composites. It also describes the advantages and limitations of the three currently used 3D bioprinting technologies: inkjet bioprinting, micro-extrusion, and laser-assisted bioprinting. Conclusions Although 3D bioprinting technology is still in its infancy and requires further development and optimization both in biomaterials and techniques, it offers great promise and potential for facial reconstruction with improved outcome

Multiscale multifactorial approaches for engineering tendon substitutes

The physiology of tendons and the continuous strains experienced daily make tendons very prone to injury. Excessive and prolonged loading forces and aging also contribute to the onset and progression of tendon injuries, and conventional treatments have limited efficacy in restoring tendon biomechanics. Tissue engineering and regenerative medicine (TERM) approaches hold the promise to provide therapeutic solutions for injured or damaged tendons despite the challenging cues of tendon niche and the lack of tendon-specific factors to guide cellular responses and tackle regeneration. The roots of engineering tendon substitutes lay in multifactorial approaches from adequate stem cells sources and environmental stimuli to the construction of multiscale 3D scaffolding systems. To achieve such advanced tendon substitutes, incremental strategies have been pursued to more closely recreate the native tendon requirements providing structural as well as physical and chemical cues combined with biochemical and mechanical stimuli to instruct cell behavior in 3D architectures, pursuing mechanically competent constructs with adequate maturation before implantation.Authors acknowledge the project “Accelerating tissue engineering and personalized medicine discoveries by the integration of key enabling nanotechnologies, marinederived biomaterials and stem cells,” supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Authors acknowledge the H2020 Achilles Twinning Project No. 810850, and also the European Research Council CoG MagTendon No. 772817, and the FCT Project MagTT PTDC/CTM-CTM/ 29930/2017 (POCI-01-0145-FEDER-29930

Pathological and Doppler Ultrasonographic Study of Kidney Hemodynamic Response in Saffron (Crocus Sativua) Pretreated Rats

Abstract Objective-To evaluate kidney hemodynamic response including blood flow velocity in segmental arteries shortly after administration of various dose of saffron extract (10, 40 and 90 mg/kg). Design-Technical assessment, experimental study. Animals-20 healthy male Sprague-Dawley rats. Procedures-In this study, using a real-time pulsed doppler analysis, kidney hemodynamic response including blood flow velocity in segmental arteries shortly after administration of various doses of saffron (10, 40 and 90 mg/kg) was investigated and eventually the data represented for each group were interpreted into tissue changes blindly. Results-Saffron at a dose of 10 mg/kg significantly increased renal blood flow with minimum tissue side effects, while at the higher doses it was remarkably associated with tissue lesions such as ATN and glomerulopathy. Conclusion and Clinical Relevance-Saffron is a scarce and valuable crop because of the stigma's charming fragrance and pleasant flavor, the aroma of which is naturally furnished by a desirable golden color when dried. Due to innate therapeutic properties, it has been a focus of interest for modern pharmacological studies to comprehensively recognize the advantages of using saffron, in the light of its low toxicity and powerful anti-oxidant properties. Beyond direct effects on the epithelial cell function, saffron significantly enhances vascular blood flow, resulting in an indirect control towards cardiovascular system. In conclusion, saffron therapy is recommended in ischemic conditions. The preferred doses ranged between 10 to 40 mg/kg. At the dose of 10 mg/kg lower tissue side effects is expected

Effect of <i>Peganum harmala</i> (wild rue) extract on experimental ovine malignant theileriosis : pathological and parasitological findings

Malignant theileriosis of sheep is a highly fatal, acute or subacute disease is caused by the tick-borne protozoan parasite, Theileria hirci. In this investigation ten healthy male lambs aged 5-6 months were randomly divided into two groups, A and B and were kept in isolated tick-proof pens. They were treated for internal and external parasite before commencement of the experiment. The lambs were experimentally infected with T. hirci by placing ticks Hyalomma anatolicum anatolicum infected with T. hirci on them. The ticks used in this survey had originally been isolated from sheep and colonies of them were established in an insectarium. Before and after infection rectal temperatures and clinical signs of the lambs were recorded, blood and prescapular lymph node smears were prepared and examined to determine the extent of the parasitaemia, and blood samples were analyzed to evaluate their haemoglobin (Hb) and packed cell volume (PCV) rates. Three days after the commencement of a febrile reaction and appearance of the schizonts in the lymph node smears, treatment of the lambs in Group A with an extract containing the alkaloids of Peganum harmala (wild rue) was commenced. Group B lambs were kept untreated controls. Before treatment there were no significant differences in the rectal temperature, parasitaemia rate, and the Hb and PCV values between animals in the two groups but after treatment significant differences in these values was detected (P < 0.05). After treatment, the clinical signs and parasites in the lymph node smears of the animals in Group A disappeared and they all animals recovered. These parameters in the animals of Group B progressed until their death. Pathological studies showed the characteristic lesions of theileriosis in lambs in Group B, but not in Group A. The results indicate a therapeutic effect of the alkaloids of P. harmala for treatment of ovine malignant theileriosis

First report of oligodendroglioma in a sheep : clinical communication

Oligodendrogliomas occur most commonly in the dog, but have also been reported in cattle, horses and cats. A 1-year-old sheep with neurological disturbances, including blindness, ataxia, circling and incoordination was referred to the veterinary clinic of Shahid Bahonar University of Kerman. Following euthanasia and necropsy, a soft, relatively well-demarcated mass was observed in the white and grey matter of the right cerebral hemisphere, close to the sylvian fissure in the right cerebral hemisphere. Microscopic examination revealed a sheet of densely packed tumour cells with hyperchromatic nuclei, lightly staining cytoplasm and characteristic perinuclear halo effect which is consistent with a diagnosis of oligodendroglioma. This is the 1st report of oligodendroglioma in sheep

Histopathologic and biomechanical comparisons of the properties of skin, sutured with an Iranian and a foreign brand Nylon suture in rat

Abstract: This study was designed to elucidate the possible differences between Supa and Ethicon, nylon in suturing rat skin. 75 Female Spragne-dawley albino rats with mean weight 250g were used and randomly divided into three groups of 30, 30 and 15 rats. In 60 rats anesthesea was induced by ketamin and xylazin. Followed by surgical preparation, a 5cm abdominal skin incision was made and sutured by simple interrupted suture pattern. In group 1, 3/0 nylon, Supa product and in group 2, 3/0 nylon Ethicon product were used. 15 animals of each group were sacrificed on day 6th for histopathologic examination and the rest of the animals on day 13th for histopathologic and biomechanical examinations. 15 rats were sacrificed for biomechanical evaluation of normal skin. Histopathologic sections were stained by H&E and examined under light microscope for reepithelization, acanthosis, age of granulation tissue, type of predominant inflammatory cells, hyperemia and the presence of giant cells. Tissue repair in group 2 was significantly more mature than group 1 on day 6th (P?0.05). There was no significant difference between the two groups on day 13th. In biomechanical study, the following parameters were measured form load-elongation curve: linear starting point, yield point, ultimate strength, stiffness, ultimate strain, maximum stored energy and yield stored energy. The stiffness of group 1 samples was significantly more than group 2 (P?0.05). There were no significant differences between the two groups in other biomechanical parameters. According to the results of this study it can be concluded that concerning short term tissue reactions, Ethicon nylon suture is superior to Supa, though there was no significant histopathologic difference between the two groups on day 13. However, cystic structures were observed only in group 2. The biomechanical quality of group 2 was also superior to group 1. Keywords: Supa nylon, Ethicon nylon, Histopathology, Biomechanics, Rat ski

A benchmark-based evaluation of search-based crash reproduction

Crash reproduction approaches help developers during debugging by generating a test case that reproduces a given crash. Several solutions have been proposed to automate this task. However, the proposed solutions have been evaluated on a limited number of projects, making comparison difficult. In this paper, we enhance this line of research by proposing JCrashPack, an extensible benchmark for Java crash reproduction, together with ExRunner, a tool to simply and systematically run evaluations. JCrashPack contains 200 stack traces from various Java projects, including industrial open source ones, on which we run an extensive evaluation of EvoCrash, the state-of-the-art tool for search-based crash reproduction. EvoCrash successfully reproduced 43% of the crashes. Furthermore, we observed that reproducing NullPointerException, IllegalArgumentException, and IllegalStateException is relatively easier than reproducing ClassCastException, ArrayIndexOutOfBoundsException and StringIndexOutOfBoundsException. Our results include a detailed manual analysis of EvoCrash outputs, from which we derive 14 current challenges for crash reproduction, among which the generation of input data and the handling of abstract and anonymous classes are the most frequents. Finally, based on those challenges, we discuss future research directions for search-based crash reproduction for Java